diff --git a/pyproject.toml b/pyproject.toml
index 5e9a985f..4822ec60 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -37,6 +37,7 @@ dev = [
   "mypy-gitlab-code-quality",
 #  "pytest-gitlab-code-quality", # pytest version constraint clashes with labthings
   "pytest",
+  "pytest-mock==3.14",
   "matplotlib~=3.10",
   "hypothesis",
 ]
diff --git a/src/openflexure_microscope_server/scan_directories.py b/src/openflexure_microscope_server/scan_directories.py
new file mode 100644
index 00000000..e2a33fbc
--- /dev/null
+++ b/src/openflexure_microscope_server/scan_directories.py
@@ -0,0 +1,315 @@
+"""
+This submodule contains functionality for interacting with scan directories.
+
+Currently it handles scan getting information from a information from a scan directory,
+eventually is should handle all the file system operation for smart_scan.
+"""
+
+from typing import Optional
+import os
+import re
+import shutil
+import zipfile
+
+from pydantic import BaseModel
+
+IMG_DIR_NAME = "images"
+IMAGE_REGEX = re.compile(r"-?[0-9]+_-?[0-9]+\.jpe?g$")
+SCAN_ZERO_PAD_DIGITS = 4
+
+
+class NotEnoughFreeSpaceError(IOError):
+    pass
+
+
+class ScanInfo(BaseModel):
+    """Summary information about a scan folder"""
+
+    name: str
+    created: float
+    modified: float
+    number_of_images: int
+    stitch_available: bool
+    dzi: Optional[str]
+
+
+class ScanDirectoryManager:
+    """
+    A class for managing interactions with scan directories
+    """
+
+    _base_scan_dir: str
+
+    def __init__(self, base_scan_dir: str):
+        self._base_scan_dir = base_scan_dir
+        if not os.path.exists(self._base_scan_dir):
+            os.makedirs(self._base_scan_dir)
+
+    @property
+    def base_dir(self) -> str:
+        """The base directory scans are saved to"""
+        return self._base_scan_dir
+
+    def exists(self, scan_name: str) -> bool:
+        """True if scan of this name exists on disk"""
+        return os.path.isdir(self.path_for(scan_name))
+
+    def path_for(self, scan_name: str) -> str:
+        """Return the path for a given scan name
+
+        Returns the path even if it doesn't exist
+        """
+        return os.path.join(self._base_scan_dir, scan_name)
+
+    def img_dir_for(self, scan_name: str) -> str:
+        """Return the path for the image dir for a given scan name
+
+        Returns the path even if it doesn't exist
+        """
+        return os.path.join(self._base_scan_dir, scan_name, IMG_DIR_NAME)
+
+    def get_file_from(
+        self, scan_name: str, filename: str, check_exists: bool = False
+    ) -> Optional[str]:
+        """Return the file path for the file within a scan directory
+
+        If check_exists is True then None will be returned if the file does
+        not exist.
+        """
+        file_path = os.path.join(self.path_for(scan_name), filename)
+        if check_exists:
+            if not os.path.exists(file_path):
+                return None
+        return file_path
+
+    def get_file_from_img_dir(
+        self, scan_name: str, filename: str, check_exists: bool = False
+    ) -> Optional[str]:
+        """Return the file path for the file within a scan directory
+
+        If check_exists is True, None is returned if the file does not exist. If False
+        then the path is returned anway
+        """
+        file_path = os.path.join(self.img_dir_for(scan_name), filename)
+        if check_exists:
+            if not os.path.exists(file_path):
+                return None
+        return file_path
+
+    @property
+    def all_scans(self) -> list[str]:
+        """Return a list of the scan names in the base directory"""
+        return [f.name for f in os.scandir(self._base_scan_dir) if f.is_dir()]
+
+    def all_scans_info(self) -> list[ScanInfo]:
+        """Return a lists of ScanInfo objects for each scan"""
+
+        all_info: list[ScanInfo] = []
+        for scan_name in self.all_scans:
+            all_info.append(ScanDirectory(scan_name, self.base_dir).scan_info())
+        return all_info
+
+    def _unique_scan_name(self, scan_name: str) -> str:
+        """Get the next unique scan name starting with the given name
+
+        For more explanation on the scan naming see `new_scan_dir`
+        """
+        # A regex with the scan name and a group for the numbers
+        scan_regex = re.compile(
+            "^" + scan_name + "_([0-9]{" + str(SCAN_ZERO_PAD_DIGITS) + "})$"
+        )
+
+        matching_scans = [scan for scan in self.all_scans if scan_regex.match(scan)]
+        if not matching_scans:
+            scan_num = 1
+        else:
+            last_matching_scan = sorted(matching_scans)[-1]
+            # Get the first group from the regex, turn to int, and add 1
+            scan_num = int(scan_regex.match(last_matching_scan)[1]) + 1
+
+        # Set a sensible limit for the number of scans of one name
+        # based on our zero padding.
+        max_scan_no = 10**SCAN_ZERO_PAD_DIGITS - 1
+
+        if scan_num > max_scan_no:
+            raise FileExistsError(
+                "Could not create a new scan folder: all names in use!"
+            )
+
+        return f"{scan_name}_{scan_num:0{SCAN_ZERO_PAD_DIGITS}d}"
+
+    def new_scan_dir(self, scan_name: str) -> "ScanDirectory":
+        """Get a unique name for this scan and create a directory for it
+
+        The scan will be named `{scan_name}_0001` where the number is
+        zero-padded to be SCAN_ZERO_PAD_DIGITS digits long (to allow correct sorting if the
+        scans are ordered alphanumerically).
+
+        Creates a new empty folder, into which scans are saved
+
+        Returns the a ScanDirectory object
+        """
+
+        # if no scan name is set set to "scan". This done here as empty strings
+        # get passed in otherwise.
+        if not scan_name:
+            scan_name = "scan"
+
+        full_scan_name = self._unique_scan_name(scan_name)
+
+        os.makedirs(self.path_for(full_scan_name))
+        os.makedirs(self.img_dir_for(full_scan_name))
+        return ScanDirectory(full_scan_name, self.base_dir)
+
+    def delete_scan(self, scan_name: str) -> None:
+        """Delete a scan"""
+        shutil.rmtree(self.path_for(scan_name))
+
+    def zip_scan(self, scan_name: str, final_version: bool = False) -> "ScanDirectory":
+        """Zips any images from the scan not yet zipped, return full path to zip
+
+        `final_version` Set true to stitch all files not just the scan images
+        this should only be done at the end as it is not possible to update a file
+        in a zip.
+        """
+        return ScanDirectory(scan_name, self.base_dir).zip_files(final_version)
+
+    def check_free_disk_space(self, min_space: int = 500000000) -> None:
+        """
+        Raise an exception if there is not enough free disk space to continue scanning
+
+        :param min_space: the minimum space required in bytes.
+            Default = 500,000,000 (500MB)
+
+        :raises: NotEnoughFreeSpaceError if the remaining storage is below min_space
+        """
+        disk_usage = shutil.disk_usage(self._base_scan_dir)
+        if disk_usage.free < min_space:
+            raise NotEnoughFreeSpaceError(
+                "There is not enough free disk space to continue. "
+                f"(Required: {min_space >> 20}MB. Free: {disk_usage.free >> 20}MB)."
+            )
+
+
+class ScanDirectory:
+    """A class for handling interactions with scan directories
+
+    Initalisation parameters:
+      name: the name of the scan (the scan directory basename)
+      base_scan_dir: Path of the directory that holds all scans
+    """
+
+    _name: str
+    _base_scan_dir: str
+
+    def __init__(self, name: str, base_scan_dir: str):
+        self._name = name
+        self._base_scan_dir = base_scan_dir
+        if not os.path.isdir(self.dir_path):
+            raise FileNotFoundError(
+                f"The scan directory {self.dir_path} cannot be found"
+            )
+
+    @property
+    def name(self) -> str:
+        """The name of the scan"""
+        return self._name
+
+    @property
+    def dir_path(self) -> str:
+        """The full path to the scan directory"""
+        return os.path.join(self._base_scan_dir, self._name)
+
+    @property
+    def images_dir(self) -> Optional[str]:
+        """
+        The path to the images directory. None is returned if no images directory
+        was created
+        """
+        im_path = os.path.join(self.dir_path, IMG_DIR_NAME)
+        if os.path.isdir(im_path):
+            return im_path
+        return None
+
+    @property
+    def created_time(self) -> float:
+        """The time the directory was created on disk"""
+        return os.path.getctime(self.dir_path)
+
+    def get_scan_files(self):
+        """Return a list of the files in the images dir"""
+        if self.images_dir is None:
+            return []
+        return os.listdir(self.images_dir)
+
+    def get_modified_time(self) -> float:
+        """Return the modified time of the directory"""
+        return max(os.stat(root).st_mtime for root, _, _ in os.walk(self.dir_path))
+
+    def scan_info(self):
+        """Return the information for the scan directory as a ScanInfo object"""
+        folder_contents = self.get_scan_files()
+        if folder_contents:
+            scan_images = [i for i in folder_contents if IMAGE_REGEX.search(i)]
+            stitches = [i for i in folder_contents if i.endswith("_stitched.jpg")]
+            dzi_files = [i for i in folder_contents if i.endswith("dzi")]
+
+            number_of_images = len(scan_images)
+            stitch_available = len(stitches) > 0
+            dzi = None if not dzi_files else str(dzi_files[0])
+        else:
+            number_of_images = 0
+            stitch_available = False
+            dzi = None
+
+        return ScanInfo(
+            name=self.name,
+            created=self.created_time,
+            modified=self.get_modified_time(),
+            number_of_images=number_of_images,
+            stitch_available=stitch_available,
+            dzi=dzi,
+        )
+
+    def all_files(self):
+        """Return a list of all files in the scan dir relative to the dir"""
+        files = []
+        for file_root, _, filenames in os.walk(self.dir_path):
+            for filename in filenames:
+                full_path = os.path.join(file_root, filename)
+                files.append(os.path.relpath(full_path, self.dir_path))
+        return files
+
+    def zip_files(self, final_version: bool = False) -> str:
+        """Zips any images from the scan not yet zipped, return full path to zip
+
+        `final_version` Set true to stitch all files not just the scan images
+        this should only be done at the end as it is not possible to update a file
+        in a zip.
+        """
+
+        zip_fname = os.path.join(self.dir_path, "images.zip")
+
+        if os.path.isfile(zip_fname):
+            # get a list of files in the existing zip
+            zip_files = get_files_in_zip(zip_fname)
+        else:
+            zip_files = []
+
+        with zipfile.ZipFile(zip_fname, mode="a") as scan_zip:
+            for file in self.all_files():
+                # Don't zip zipfiles, or files in the zip
+                if file.endswith(".zip") or file in zip_files:
+                    continue
+                # If this is not the final version, then only zip image files.
+                if not final_version and not IMAGE_REGEX.search(file):
+                    continue
+
+                scan_zip.write(os.path.join(self.dir_path, file), arcname=file)
+        return zip_fname
+
+
+def get_files_in_zip(zip_path):
+    """List the relative paths of all files and folders in the zip folder specified"""
+    scan_zip = zipfile.ZipFile(zip_path)
+    return [os.path.normpath(i) for i in scan_zip.namelist()]
diff --git a/src/openflexure_microscope_server/things/smart_scan.py b/src/openflexure_microscope_server/things/smart_scan.py
index b206058a..832f6170 100644
--- a/src/openflexure_microscope_server/things/smart_scan.py
+++ b/src/openflexure_microscope_server/things/smart_scan.py
@@ -1,19 +1,15 @@
-import shutil
-import zipfile
-import threading
 from typing import Optional, Mapping
+import threading
+import os
+import time
+import json
+from datetime import datetime
+from subprocess import CompletedProcess, Popen, PIPE, SubprocessError, STDOUT
+
 from fastapi import HTTPException
 from fastapi.responses import FileResponse
 import numpy as np
-import os
-import time
 from PIL import Image
-from pydantic import BaseModel
-from datetime import datetime
-from subprocess import CompletedProcess, Popen, PIPE, SubprocessError, STDOUT
-import glob
-import json
-import re
 
 from labthings_fastapi.thing import Thing
 from labthings_fastapi.dependencies.metadata import GetThingStates
@@ -25,74 +21,37 @@ from labthings_fastapi.dependencies.invocation import (
 )
 from labthings_fastapi.decorators import thing_action, thing_property, fastapi_endpoint
 from labthings_fastapi.outputs.blob import blob_type
-from .camera import CameraDependency as CamDep
-from .stage import StageDependency as StageDep
 
 from openflexure_microscope_server.utilities import ErrorCapturingThread
-from openflexure_microscope_server.things.autofocus import AutofocusThing
-from openflexure_microscope_server.things.camera_stage_mapping import CameraStageMapper
-from openflexure_microscope_server.things.background_detect import BackgroundDetectThing
+from openflexure_microscope_server import scan_directories
 from openflexure_microscope_server import scan_planners
 
+# Things
+from .autofocus import AutofocusThing
+from .camera_stage_mapping import CameraStageMapper
+from .background_detect import BackgroundDetectThing
+from .camera import CameraDependency as CamDep
+from .stage import StageDependency as StageDep
+
 CSMDep = direct_thing_client_dependency(CameraStageMapper, "/camera_stage_mapping/")
 AutofocusDep = direct_thing_client_dependency(AutofocusThing, "/autofocus/")
 BackgroundDep = direct_thing_client_dependency(
     BackgroundDetectThing, "/background_detect/"
 )
 
-IMAGE_REGEX = re.compile(r"-?[0-9]+_-?[0-9]+\.jpe?g$")
-
-
-class NotEnoughFreeSpaceError(IOError):
-    pass
-
-
-def ensure_free_disk_space(path: str, min_space: int = 500000000) -> None:
-    """
-    Raise an exception if we are running out of disk space
-
-    Args:
-       path =  path to a location on the disk you want to check
-       min_space [int] = the minimum space required in bytes
-           default = 500,000,000 (500MiB)
-
-    Raises:
-        NotEnoughFreeSpaceError if the remaining storage is below min_space
-    """
-    disk_usage = shutil.disk_usage(path)
-    if disk_usage.free < min_space:
-        raise NotEnoughFreeSpaceError(
-            "There is not enough free disk space to continue. "
-            f"(Required: {min_space >> 20}MB, free: {disk_usage.free >> 20}MB)."
-        )
-
-
-class ScanInfo(BaseModel):
-    """Summary information about a scan folder"""
-
-    name: str
-    created: datetime
-    modified: datetime
-    number_of_images: int
-    stitch_available: bool
-    dzi: Optional[str]
-
-
-DOWNLOADABLE_SCAN_FILES = (
-    "images.zip",
-    "stitched_thumbnail.jpg",
-)
-
 JPEGBlob = blob_type("image/jpeg")
 ZipBlob = blob_type("application/zip")
-IMG_DIR_NAME = "images"
+
 SCAN_DATA_FILENAME = "scan_data.json"
 STITCHING_CMD = "openflexure-stitch"
 
-SCAN_ZERO_PAD_DIGITS = 4
 STITCHING_RESOLUTION = (820, 616)
 
 
+class ScanNotRunningError(RuntimeError):
+    """Exception called when scan not running that requires a scan to be running"""
+
+
 def _scan_running(method):
     """
     This decorator is used by all methods in SmartScanThing that are using
@@ -105,7 +64,7 @@ def _scan_running(method):
         # Only start the method is the scan logger is set
         if self._scan_logger is not None:
             return method(self, *args, **kwargs)
-        raise RuntimeError(
+        raise ScanNotRunningError(
             "Calling a @scan_running method can only be done while a scan is running!"
         )
 
@@ -114,7 +73,7 @@ def _scan_running(method):
 
 class SmartScanThing(Thing):
     def __init__(self, scans_folder):
-        self._scans_folder = scans_folder
+        self._scan_dir_manager = scan_directories.ScanDirectoryManager(scans_folder)
         self._preview_stitch_popen = None
         self._preview_stitch_popen_lock = threading.Lock()
         self._scan_lock = threading.Lock()
@@ -136,7 +95,7 @@ class SmartScanThing(Thing):
         self._metadata_getter: Optional[GetThingStates] = None
         self._csm: Optional[CSMDep] = None
         self._background_detect: Optional[BackgroundDep] = None
-        self._ongoing_scan_name: Optional[str] = None
+        self._ongoing_scan: Optional[scan_directories.ScanDirectory] = None
         self._starting_position: Optional[Mapping[str, int]] = None
         self._capture_thread: Optional[ErrorCapturingThread] = None
         self._scan_images_taken: Optional[int] = None
@@ -179,12 +138,14 @@ class SmartScanThing(Thing):
         self._capture_thread = None
         self._scan_images_taken = 0
 
-        # Don't set self._scan_data dictionary. This is done at the start of _run_scan
+        # Set _scan_data to None. This is needed just in case an exception is raised
+        # before _run_scan (which sets the real data). As we check this in the `except`
+        self._scan_data = None
 
         try:
             self._check_background_and_csm_set()
-            self._ongoing_scan_name = self._get_unique_scan_name_and_dir(scan_name)
-            self.create_zip_of_scan(scan_name=self._ongoing_scan_name)
+            self._ongoing_scan = self._scan_dir_manager.new_scan_dir(scan_name)
+            self._latest_scan_name = self._ongoing_scan.name
             self._autofocus.looping_autofocus(dz=self.autofocus_dz, start="centre")
             # record starting position so we can return there
             self._starting_position = self._stage.position
@@ -193,8 +154,8 @@ class SmartScanThing(Thing):
             # If _scan_data is set then scan started
             if self._scan_data is not None:
                 self._return_to_starting_position()
-                if not isinstance(e, NotEnoughFreeSpaceError):
-                    # Don't stich if drive is full (already logged)
+                if not isinstance(e, scan_directories.NotEnoughFreeSpaceError):
+                    # Don't stitch if drive is full (already logged)
                     self._perform_final_stitch()
             # Error must be raised so UI gives correct output
             raise e
@@ -209,35 +170,11 @@ class SmartScanThing(Thing):
             self._csm = None
             self._background_detect = None
             self._capture_thread = None
-            self._ongoing_scan_name = None
+            self._ongoing_scan = None
             self._scan_images_taken = None
             self._scan_data = None
             self._scan_lock.release()
 
-    def promote_stitch_files(
-        self,
-        logger,
-    ):
-        """Copy the stitched image from the scan images folder to the top level"""
-
-        # Search the scan images dir for a file ending in '_stitched.jpg
-        stitched_image_path = glob.glob(
-            os.path.join(self._ongoing_scan_images_dir, "*_stitched.jpg")
-        )
-
-        if len(stitched_image_path) == 0:
-            logger.warning("Could't find a stitched image to copy")
-        else:
-            for stitched_image in stitched_image_path:
-                stitch_name = os.path.basename(stitched_image)
-
-                shutil.copy(
-                    stitched_image,
-                    os.path.join(
-                        self.dir_for_scan(self._ongoing_scan_name), stitch_name
-                    ),
-                )
-
     @_scan_running
     def _check_background_and_csm_set(self):
         """Before starting a scan, check that background and camera-stage-mapping are set
@@ -268,88 +205,11 @@ class SmartScanThing(Thing):
                 "of motion."
             )
 
-    @property
-    def base_scan_dir(self) -> str:
-        """The path of the directory where the scans are saved."""
-        return self._scans_folder
-
     @thing_property
     def latest_scan_name(self) -> Optional[str]:
         """The name of the last scan to be started."""
         return self._latest_scan_name
 
-    def dir_for_scan(self, scan_name: str):
-        """The path to the scan directory for scan with input name"""
-        return os.path.join(self.base_scan_dir, scan_name)
-
-    def images_dir_for_scan(self, scan_name: str) -> str:
-        """The path to the images directory for scan with input name"""
-        scan_dir = self.dir_for_scan(scan_name=scan_name)
-        return os.path.join(scan_dir, IMG_DIR_NAME)
-
-    @property
-    @_scan_running
-    def _ongoing_scan_dir(self):
-        """For the ongoing scan, this returns the scan directory"""
-        if not self._ongoing_scan_name:
-            raise RuntimeError("Cannot get ongoing scan name while no scan is running")
-        return self.dir_for_scan(self._ongoing_scan_name)
-
-    @property
-    @_scan_running
-    def _ongoing_scan_images_dir(self):
-        """For the ongoing scan, this returns the image directory"""
-        if not self._ongoing_scan_name:
-            raise RuntimeError("Cannot get ongoing scan name while no scan is running")
-        return self.images_dir_for_scan(self._ongoing_scan_name)
-
-    @_scan_running
-    def _get_unique_scan_name_and_dir(self, scan_name: str) -> str:
-        """Get a unique name for this scan and create a directory for it
-
-        The scan will be named `{scan_name}_0001` where the number is
-        zero-padded to be 4 digits long (to allow correct sorting if the
-        scans are ordered alphanumerically).
-
-        Note that if you have discontinuous numbering (e.g. you've got scans
-        numbered 1 through 10, but you deleted scan 5), then the gaps will
-        get filled in - so there's no guarantee, for now, that the numbers
-        will correspond to order of creation. This may change in the future.
-
-        Creates a new empty folder, into which scans are saved
-
-        Returns the scan name.
-
-        The directory can be accessed by self.dir_for_scan(unique_scan_name)
-
-        """
-        if not os.path.exists(self.base_scan_dir):
-            os.makedirs(self.base_scan_dir)
-
-        # if no scan name is set set to "scan". This done here as empty strings
-        # get passed in otherwise.
-        if not scan_name:
-            scan_name = "scan"
-
-        # Set a sensible limit for the number of scans of one name
-        # based on our zero padding.
-        max_scan_no = 10**SCAN_ZERO_PAD_DIGITS - 1
-
-        for j in range(max_scan_no):
-            trial_unique_scan_name = f"{scan_name}_{j:0{SCAN_ZERO_PAD_DIGITS}d}"
-            trial_dir = self.dir_for_scan(trial_unique_scan_name)
-            if not os.path.exists(trial_dir):
-                os.makedirs(trial_dir)
-                # If we made the directory this is the scan name
-                # Save the scan name as the latest scan (this persists as a
-                # property after the scan finishes)
-                self._latest_scan_name = trial_unique_scan_name
-                # Create images directory and
-                os.mkdir(self.images_dir_for_scan(trial_unique_scan_name))
-                # Return the scan name
-                return trial_unique_scan_name
-        raise FileExistsError("Could not create a new scan folder: all names in use!")
-
     @_scan_running
     def _move_to_next_point(
         self, next_point: tuple[int, int], z_estimate: Optional[int] = None
@@ -443,7 +303,7 @@ class SmartScanThing(Thing):
 
         # Fix scan parameters in case UI is updated during scan.
         self._scan_data = {
-            "scan_name": self._ongoing_scan_name,
+            "scan_name": self._ongoing_scan.name,
             "overlap": overlap,
             "max_dist": self.max_range,
             "dx": dx,
@@ -466,7 +326,7 @@ class SmartScanThing(Thing):
         # Should this be a method of the scan_data dataclass?
 
         data = {
-            "scan_name": self._ongoing_scan_name,
+            "scan_name": self._ongoing_scan.name,
             "overlap": self._scan_data["overlap"],
             "autofocus range": self._scan_data["autofocus_dz"],
             "dx": self._scan_data["dx"],
@@ -477,7 +337,7 @@ class SmartScanThing(Thing):
         }
 
         scan_inputs_fname = os.path.join(
-            self._ongoing_scan_images_dir, SCAN_DATA_FILENAME
+            self._ongoing_scan.images_dir, SCAN_DATA_FILENAME
         )
         with open(scan_inputs_fname, "w", encoding="utf-8") as f:
             json.dump(data, f, ensure_ascii=False, indent=4)
@@ -506,7 +366,7 @@ class SmartScanThing(Thing):
         }
 
         scan_data_fname = os.path.join(
-            self._ongoing_scan_images_dir, SCAN_DATA_FILENAME
+            self._ongoing_scan.images_dir, SCAN_DATA_FILENAME
         )
 
         with open(scan_data_fname, encoding="utf-8") as f:
@@ -558,7 +418,7 @@ class SmartScanThing(Thing):
             scan_successful = False
             self._scan_logger.info("Stopping scan because it was cancelled.")
             self._update_scan_data_json(scan_result="cancelled by user")
-        except NotEnoughFreeSpaceError as e:
+        except scan_directories.NotEnoughFreeSpaceError as e:
             scan_successful = False
             self._update_scan_data_json(scan_result=str(e))
             self._scan_logger.error(
@@ -627,7 +487,7 @@ class SmartScanThing(Thing):
         # captures an image if necessary, updates the scan path and future path,
         # and updates the zip file with new images.
         while not route_planner.scan_complete:
-            ensure_free_disk_space(self._ongoing_scan_dir)
+            self._scan_dir_manager.check_free_disk_space()
             self._manage_stitching_threads()
 
             next_pos_xy, z_est = route_planner.get_next_location_and_z_estimate()
@@ -654,7 +514,7 @@ class SmartScanThing(Thing):
                 continue
 
             focused, focused_height = self._autofocus.run_smart_stack(
-                images_dir=self._ongoing_scan_images_dir,
+                images_dir=self._ongoing_scan.images_dir,
                 autofocus_dz=self._scan_data["autofocus_dz"],
                 save_resolution=self._scan_data["save_resolution"],
             )
@@ -665,12 +525,10 @@ class SmartScanThing(Thing):
                 current_pos_xyz, imaged=True, focused=focused
             )
 
-            # increment capure counter as thread has completed
+            # increment capture counter as thread has completed
             self._scan_images_taken += 1
             # Add it to the incremental zip
-            self.update_zip(
-                scan_name=self._ongoing_scan_name,
-            )
+            self._ongoing_scan.zip_files()
 
     @_scan_running
     def _return_to_starting_position(self):
@@ -689,10 +547,8 @@ class SmartScanThing(Thing):
             self._scan_logger.info("Not performing a stitch as 3 or fewer images taken")
             return
 
-        self.update_zip(
-            scan_name=self._ongoing_scan_name,
-            final_version=False,
-        )
+        self._ongoing_scan.zip_files()
+
         self._scan_logger.info("Waiting for background processes to finish...")
 
         self._preview_stitch_wait()
@@ -701,11 +557,10 @@ class SmartScanThing(Thing):
                 self._scan_logger.info("Stitching final image (may take some time)...")
                 self.stitch_scan(
                     logger=self._scan_logger,
-                    scan_name=self._ongoing_scan_name,
+                    scan_name=self._ongoing_scan.name,
                     stitch_resize=self._scan_data["stitch_resize"],
                     overlap=self._scan_data["overlap"],
                 )
-                self.promote_stitch_files(self._scan_logger)
         except SubprocessError as e:
             self._scan_logger.error(f"Stitching failed: {e}", exc_info=e)
 
@@ -725,12 +580,12 @@ class SmartScanThing(Thing):
 
         This endpoint allows files to be downloaded from a scan.
         """
-        path = os.path.join(
-            self.images_dir_for_scan(scan_name), "stitched_thumbnail.jpg"
+        preview_path = self._scan_dir_manager.get_file_from_img_dir(
+            scan_name=scan_name, filename="stitched_thumbnail.jpg", check_exists=True
         )
-        if not os.path.isfile(path):
+        if preview_path is None:
             raise HTTPException(404, "File not found")
-        return FileResponse(path)
+        return FileResponse(preview_path)
 
     @thing_property
     def save_resolution(self) -> tuple[int, int]:
@@ -800,7 +655,7 @@ class SmartScanThing(Thing):
         self.thing_settings["stitch_automatically"] = value
 
     @thing_property
-    def scans(self) -> list[ScanInfo]:
+    def scans(self) -> list[scan_directories.ScanInfo]:
         """All the available scans
 
         Each scan has a name (which can be used to access it), along with
@@ -809,77 +664,14 @@ class SmartScanThing(Thing):
         uses a regular expression, and changes to the naming scheme will
         break it.
         """
-        scans: list[ScanInfo] = []
-        if not os.path.isdir(self.base_scan_dir):
-            return scans
-        for f in os.listdir(self.base_scan_dir):
-            path = os.path.join(self.base_scan_dir, f)
-            if os.path.isdir(path):
-                images_folder = os.path.join(path, IMG_DIR_NAME)
-                if os.path.isdir(images_folder):
-                    folder_contents = os.listdir(images_folder)
-                    scan_images = [i for i in folder_contents if IMAGE_REGEX.search(i)]
-                    stitches = [
-                        i for i in folder_contents if i.endswith("_stitched.jpg")
-                    ]
-                    number_of_images = len(scan_images)
-                    stitch_available = len(stitches) > 0
-                    dzi = [i for i in folder_contents if i.endswith("dzi")]
-                    if len(dzi) > 0:
-                        dzi = str(dzi[0])
-                    else:
-                        dzi = None
-                else:
-                    number_of_images = 0
-                    stitch_available = False
-                modified = max(os.stat(root).st_mtime for root, _, _ in os.walk(path))
-
-                scans.append(
-                    ScanInfo(
-                        name=f,
-                        created=os.path.getctime(path),
-                        modified=modified,
-                        number_of_images=number_of_images,
-                        stitch_available=stitch_available,
-                        dzi=dzi,
-                    )
-                )
-        return scans
-
-    @fastapi_endpoint(
-        "get",
-        "scans/{scan_name}/{file}",
-        responses={
-            200: {
-                "description": "Successfully downloading file",
-                "content": {"*/*": {}},
-            },
-            403: {"description": "Filename not permitted"},
-            404: {"description": "File not found"},
-        },
-    )
-    def get_scan_file(self, scan_name: str, file: str) -> FileResponse:
-        """Retrieve a file from a scan.
-
-        This endpoint allows files to be downloaded from a scan. For security
-        reasons, there is a list of allowable filenames, and paths with additional
-        slashes are not permitted.
-        """
-        if file not in DOWNLOADABLE_SCAN_FILES:
-            raise HTTPException(
-                403, f"You may only download files named {DOWNLOADABLE_SCAN_FILES}"
-            )
-        path = os.path.join(self.base_scan_dir, scan_name, file)
-        if not os.path.isfile(path):
-            raise HTTPException(404, "File not found")
-        return FileResponse(path)
+        return self._scan_dir_manager.all_scans_info()
 
     @fastapi_endpoint(
         "delete",
         "scans/{scan_name}",
         responses={
             200: {"description": "Successfully deleted scan"},
-            404: {"description": "Scan not found"},
+            400: {"description": "An error occurred while trying to delete scan"},
         },
     )
     def delete_scan(self, scan_name: str, logger: InvocationLogger) -> None:
@@ -889,11 +681,10 @@ class SmartScanThing(Thing):
 
         Takes the scan name to delete, and the Invocation Logger
         """
-        path = os.path.join(self.base_scan_dir, scan_name)
-        if not os.path.isdir(path):
-            logger.info(f"can't find {path}")
+        if not self._scan_dir_manager.exists(scan_name):
+            logger.warning(f"Cannot find a scan of name {scan_name}")
             raise HTTPException(400, "Scan not found")
-        deleted_scan_success = self._delete_scan(path, logger)
+        deleted_scan_success = self._delete_scan(scan_name, logger)
         if not deleted_scan_success:
             raise HTTPException(400, "Couldn't delete scan, check log for details")
 
@@ -908,49 +699,59 @@ class SmartScanThing(Thing):
         microscope!**
         Use with extreme caution.
         """
-        for scan in self.scans:
-            path = os.path.join(self.base_scan_dir, scan.name)
-            self._delete_scan(path, logger)
+        for scan_name in self._scan_dir_manager.all_scans:
+            self._delete_scan(scan_name, logger)
 
     @thing_action
-    def _delete_scan(self, scan_path, logger: InvocationLogger) -> bool:
+    def purge_empty_scans(self, logger: InvocationLogger) -> None:
+        """
+        Delete all scan folders containing no images at the top level
+        """
+
+        # JSON is ignored as it's created before any images are captured
+        for scan_info in self._scan_dir_manager.all_scans_info():
+            if scan_info.number_of_images == 0:
+                self._delete_scan(scan_info.name, logger)
+
+    def _delete_scan(self, scan_name, logger: InvocationLogger) -> bool:
+        """
+        A wrapper around scan manager's delete_scan that logs to the invocation logger
+        """
         try:
-            shutil.rmtree(scan_path)
+            self._scan_dir_manager.delete_scan(scan_name)
             return True
         except Exception as e:
             logger.warning(
-                "Attempted to delete scan " + scan_path + ", which failed."
+                "Attempted to delete scan " + scan_name + ", which failed."
                 " Server sent response" + str(e)
             )
             return False
 
     @property
-    def latest_preview_stitch_path(self):
-        """Return the path of the latest preview stitched image
+    def latest_preview_stitch_path(self) -> Optional[str]:
+        """The path of the latest preview stitched image, or None if not available"""
 
-        If the image cannot be found (because there is no latest
-        scan, or because the latest scan has no preview stitch) then
-        raise FileNotFoundError
-        """
         if not self.latest_scan_name:
-            raise FileNotFoundError("No latest scan found")
+            return None
 
-        images_dir = self.images_dir_for_scan(self.latest_scan_name)
-        stitch_path = os.path.join(images_dir, "preview.jpg")
-        if not os.path.isfile(stitch_path):
-            raise FileNotFoundError("Latest scan has no preview stitch")
-        return stitch_path
+        return self._scan_dir_manager.get_file_from_img_dir(
+            scan_name=self.latest_scan_name, filename="preview.jpg", check_exists=True
+        )
 
     @thing_property
-    def latest_preview_stitch_time(self) -> Optional[datetime]:
-        """The modification time of the latest preview image
+    def latest_preview_stitch_time(self) -> Optional[float]:
+        """The modification time of the latest preview image, to allow live updating
 
-        This will return `null` if there is no preview image to return.
+        This will return None (`null` to JS) if there is no preview image to return.
+
+        This is used for two reasons:
+        1. If all caching was turned off this stitch would be sent over the network
+           repeatedly
+        2. If caching was is on, then the stitch will not update when needed.
         """
-        try:
-            return os.path.getmtime(self.latest_preview_stitch_path)
-        except FileNotFoundError:
+        if self.latest_preview_stitch_path is None:
             return None
+        return os.path.getmtime(self.latest_preview_stitch_path)
 
     @fastapi_endpoint(
         "get",
@@ -965,10 +766,10 @@ class SmartScanThing(Thing):
     )
     def get_latest_preview(self) -> FileResponse:
         """Retrieve the latest preview image."""
-        try:
-            return FileResponse(self.latest_preview_stitch_path)
-        except FileNotFoundError:
+        preview_path = self.latest_preview_stitch_path
+        if preview_path is None:
             raise HTTPException(404, "File not found")
+        return FileResponse(preview_path)
 
     @_scan_running
     def _preview_stitch_start(self, overlap: float) -> None:
@@ -996,7 +797,7 @@ class SmartScanThing(Thing):
                     f"{min_overlap}",
                     "--resize",
                     f"{self._scan_data['stitch_resize']}",
-                    self._ongoing_scan_images_dir,
+                    self._ongoing_scan.images_dir,
                 ]
             )
 
@@ -1074,8 +875,9 @@ class SmartScanThing(Thing):
         Note that as this is a thing_action it needs the logger passed as
         a variable if called from another thing action
         """
-        images_folder = self.images_dir_for_scan(scan_name=scan_name)
-        json_fpath = os.path.join(images_folder, SCAN_DATA_FILENAME)
+        json_fpath = self._scan_dir_manager.get_file_from_img_dir(
+            scan_name=scan_name, filename=SCAN_DATA_FILENAME
+        )
 
         if self.stitch_tiff:
             tiff_arg = "--stitch_tiff"
@@ -1137,87 +939,10 @@ class SmartScanThing(Thing):
                 f"{round(overlap * 0.9, 2)}",
                 "--resize",
                 f"{stitch_resize}",
-                images_folder,
+                self._scan_dir_manager.img_dir_for(scan_name),
             ],
         )
 
-    @thing_action
-    def create_zip_of_scan(
-        self,
-        scan_name: str,
-    ) -> None:
-        """Generate an empty zip file for the current scan"""
-        images_folder = self.images_dir_for_scan(scan_name=scan_name)
-        scan_folder = self.dir_for_scan(scan_name=scan_name)
-
-        if not os.path.isdir(images_folder):
-            raise FileNotFoundError(
-                f"Tried to make a zip archive of {images_folder} but it does not exist."
-            )
-
-        zip_fname = os.path.join(scan_folder, "images.zip")
-
-        # Create an empty zip file
-        if not os.path.isfile(zip_fname):
-            with zipfile.ZipFile(zip_fname, mode="w"):
-                pass
-
-    def update_zip(
-        self,
-        scan_name: str,
-        final_version: bool = False,
-    ) -> None:
-        """Update the zip file with any images added to the folder since the last run,
-        except for files containing 'files_to_delay', which are files to only include
-        once the scan is finished or the user wants to download the zip
-        """
-        scan_folder = self.dir_for_scan(scan_name=scan_name)
-
-        zip_fname = os.path.join(scan_folder, "images.zip")
-
-        # get a list of files in the existing zip
-        current_zip = self.get_files_in_zip(zip_fname)
-
-        # get a list of files in the folder we're zipping
-
-        files = glob.glob(scan_folder + "/**/*", recursive=True)
-        files = [os.path.relpath(file, scan_folder) for file in files]
-
-        # This is a list of file names that are updated as the scan goes,
-        # and should only be zipped at the end of the scan - otherwise they'll
-        # be appended on every loop as we can't overwrite files in the zip
-
-        # More elegant ways would be to only zip the images matching the global regex,
-        # which will all be images, then append other files at the end.
-        # Alternatively, use "output_dir" in stitching to separate stitching image files
-        files_to_delay = [
-            "TileConfiguration",
-            "tiling_cache",
-            "stitched.jp",
-            "stitched_from",
-            "stitched.om",
-            "stitching_correlations",
-            "preview.jp",
-        ]
-
-        with zipfile.ZipFile(zip_fname, mode="a") as scan_zip:
-            for file in files:
-                if any(skipped_name in file for skipped_name in files_to_delay):
-                    pass
-                elif file in current_zip:
-                    pass
-                elif ".zip" in file:
-                    pass
-                else:
-                    scan_zip.write(os.path.join(scan_folder, file), arcname=file)
-
-        # Finally, zip the files skipped previously
-        if final_version:
-            with zipfile.ZipFile(zip_fname, mode="a") as scan_zip:
-                for file in files:
-                    if any(delayed_name in file for delayed_name in files_to_delay):
-                        scan_zip.write(os.path.join(scan_folder, file), arcname=file)
-
     @thing_action
     def download_zip(
         self,
@@ -1225,43 +950,5 @@ class SmartScanThing(Thing):
     ):
         """Update the zip to include the files left until the end, then return the
         zip file as a Blob"""
-        self.update_zip(
-            scan_name=scan_name,
-            final_version=True,
-        )
-
-        scan_folder = self.dir_for_scan(scan_name=scan_name)
-
-        zip_fname = os.path.join(scan_folder, "images.zip")
+        zip_fname = self._scan_dir_manager.zip_scan(scan_name, final_version=True)
         return ZipBlob.from_file(zip_fname)
-
-    def get_files_in_zip(self, zip_path):
-        """List the relative paths of all files and folders in the zip folder specified"""
-        scan_zip = zipfile.ZipFile(zip_path)
-        return [os.path.normpath(i) for i in scan_zip.namelist()]
-
-    @thing_action
-    def purge_empty_scans(self, logger: InvocationLogger) -> None:
-        """
-        Delete all scan folders containing no images at the top level
-        """
-        scan_list = self.scans
-
-        # Filter out scans with no top level files, ignoring JSON files
-        # JSON is ignored as it's created before any images are captured
-        for scan in scan_list:
-            scan_folder = os.path.join(self.base_scan_dir, scan.name, IMG_DIR_NAME)
-            images_found = False
-            # Check the scan directory exists, and if it does loop through each file
-            # to check if they are scan captures.
-            if os.path.isdir(scan_folder):
-                for fname in os.listdir(scan_folder):
-                    fpath = os.path.join(scan_folder, fname)
-                    if os.path.isfile(fpath) and IMAGE_REGEX.search(fname):
-                        images_found = True
-                        # break as soon as an image is found.
-                        break
-
-            if not images_found:
-                path = os.path.join(self.base_scan_dir, scan.name)
-                self._delete_scan(path, logger)
diff --git a/tests/mock_things/__init__.py b/tests/mock_things/__init__.py
new file mode 100644
index 00000000..e69de29b
diff --git a/tests/mock_things/mock_autofocus.py b/tests/mock_things/mock_autofocus.py
new file mode 100644
index 00000000..d32b5a50
--- /dev/null
+++ b/tests/mock_things/mock_autofocus.py
@@ -0,0 +1,17 @@
+"""This testing submodule contains mock autofocus things.
+
+These mocks are designed to be inserted as dependencies to give specific
+functionality and returns.
+
+The mocks do not subclass, and instead return very specific defined answers
+to functions
+"""
+
+
+class MockAutoFocusThing:
+    # Counter for checking functions were called
+    mock_call_count = {"looping_autofocus": 0}
+
+    def looping_autofocus(self, dz: int = 2000, start: str = "centre") -> None:  # noqa: ARG002
+        """This function mocks autofocus with no return"""
+        self.mock_call_count["looping_autofocus"] += 1
diff --git a/tests/mock_things/mock_background_detect.py b/tests/mock_things/mock_background_detect.py
new file mode 100644
index 00000000..f79a1059
--- /dev/null
+++ b/tests/mock_things/mock_background_detect.py
@@ -0,0 +1,18 @@
+"""This testing submodule contains mock background detect things.
+
+These mocks are designed to be inserted as dependencies to give specific
+functionality and returns.
+
+The mocks do not subclass, and instead return very specific defined answers
+to functions
+"""
+
+from openflexure_microscope_server.things.background_detect import ChannelDistributions
+
+
+class MockBackgoundDetectThing:
+    background_distributions = ChannelDistributions(
+        means=[128.0, 128.0, 128.0],
+        standard_deviations=[3.0, 3.0, 3.0],
+        colorspace="LUV",
+    )
diff --git a/tests/mock_things/mock_csm.py b/tests/mock_things/mock_csm.py
new file mode 100644
index 00000000..78930dae
--- /dev/null
+++ b/tests/mock_things/mock_csm.py
@@ -0,0 +1,12 @@
+"""This testing submodule contains mock camera stage mapping things.
+
+These mocks are designed to be inserted as dependencies to give specific
+functionality and returns.
+
+The mocks do not subclass, and instead return very specific defined answers
+to functions
+"""
+
+
+class MockCSMThing:
+    image_resolution = (123, 456)
diff --git a/tests/mock_things/mock_stage.py b/tests/mock_things/mock_stage.py
new file mode 100644
index 00000000..9b7a466d
--- /dev/null
+++ b/tests/mock_things/mock_stage.py
@@ -0,0 +1,12 @@
+"""This testing submodule contains stage things.
+
+These mocks are designed to be inserted as dependencies to give specific
+functionality and returns.
+
+The mocks do not subclass, and instead return very specific defined answers
+to functions
+"""
+
+
+class MockStageThing:
+    position = (111, 222, 333)
diff --git a/tests/test_scan_directories.py b/tests/test_scan_directories.py
new file mode 100644
index 00000000..ee76c9ab
--- /dev/null
+++ b/tests/test_scan_directories.py
@@ -0,0 +1,332 @@
+import tempfile
+import os
+import shutil
+import logging
+import random
+import time
+from collections import namedtuple
+
+import pytest
+
+from openflexure_microscope_server.scan_directories import (
+    ScanDirectoryManager,
+    ScanDirectory,
+    ScanInfo,
+    get_files_in_zip,
+    NotEnoughFreeSpaceError,
+)
+
+# A global logger to pass in as an Invocation Logger
+LOGGER = logging.getLogger("mock-invocation_logger")
+
+# Use our own dir in the root temp dir not a dynamically generated one so we
+# have some control of when it is deleted
+BASE_SCAN_DIR = os.path.join(tempfile.gettempdir(), "scans")
+
+
+def _clear_scan_dir() -> None:
+    """Delete the scan dir"""
+    if os.path.exists(BASE_SCAN_DIR):
+        shutil.rmtree(BASE_SCAN_DIR)
+
+
+def _add_fake_image(scan_dir: ScanDirectory) -> None:
+    """Make a fake image on disk in the scan directory"""
+    x_pos = random.randint(-100, 100)
+    y_pos = random.randint(-100, 100)
+    filename = f"image_{x_pos}_{y_pos}.jpg"
+    filepath = os.path.join(scan_dir.images_dir, filename)
+    with open(filepath, "w") as f_obj:
+        f_obj.write("fake")
+
+
+def _add_fake_file(
+    scan_dir: ScanDirectory, filename: str, in_im_dir: bool = False
+) -> None:
+    """Make a fake file on disk in the scan directory.
+
+    :param in_im_dir: Boolean, if set True the fake file is created in the images
+    directory of the scan not the root directory.
+    """
+    if in_im_dir:
+        filepath = os.path.join(scan_dir.images_dir, filename)
+    else:
+        filepath = os.path.join(scan_dir.dir_path, filename)
+    with open(filepath, "w") as f_obj:
+        f_obj.write("fake")
+
+
+def test_basic_directory_operations():
+    """Test some basic operations
+
+    Test some basic operations, including:
+    - ScanDirectoryManager creates a scan directory
+    - For a fake (dummy) scan, a path can be created and retrieved
+    - For a fake (dummy) file, a path can be created and retrieved (for both a .zip and .img file)
+    - When a scan directory is created, the directory exists as does the image directory
+    - Scan directories can be deleted and scans can be cleared
+    """
+    _clear_scan_dir()
+    assert not os.path.isdir(BASE_SCAN_DIR)
+    scan_dir_manager = ScanDirectoryManager(BASE_SCAN_DIR)
+    # Check it makes the scan directory
+    assert os.path.isdir(BASE_SCAN_DIR)
+
+    # Considering a fake scan
+    scan_name = "fake_scan_0001"
+    scan_path = os.path.join(BASE_SCAN_DIR, scan_name)
+    scan_im_dir = os.path.join(BASE_SCAN_DIR, scan_name, "images")
+
+    # It doesn't exist but we can check its paths
+    assert not scan_dir_manager.exists(scan_name)
+    assert not os.path.isdir(scan_path)
+    assert scan_dir_manager.path_for(scan_name) == scan_path
+    assert scan_dir_manager.img_dir_for(scan_name) == scan_im_dir
+
+    # Get the path of a fake file
+    fake_file = scan_dir_manager.get_file_from(scan_name, "foo.zip")
+    assert fake_file == os.path.join(scan_path, "foo.zip")
+    # But this is none if we check it exists
+    fake_file = scan_dir_manager.get_file_from(scan_name, "foo.zip", check_exists=True)
+    assert fake_file is None
+
+    # Get the path of another fake file
+    fake_file = scan_dir_manager.get_file_from_img_dir(scan_name, "bar.img")
+    assert fake_file == os.path.join(scan_im_dir, "bar.img")
+    # But this is none if we check it exists
+    fake_file = scan_dir_manager.get_file_from_img_dir(
+        scan_name, "bar.img", check_exists=True
+    )
+    assert fake_file is None
+
+    # Create the dir
+    scan_dir = scan_dir_manager.new_scan_dir("fake_scan")
+    # This returns a ScanDirectory object
+    assert isinstance(scan_dir, ScanDirectory)
+    # The directory now exists as does the image directory
+    assert scan_dir_manager.exists(scan_name)
+    assert os.path.isdir(scan_path)
+    assert os.path.isdir(scan_im_dir)
+
+    # Test cleanup. Delete the created scan and scan directory
+    scan_dir_manager.delete_scan(scan_name)
+    assert not scan_dir_manager.exists(scan_name)
+    assert not os.path.isdir(scan_path)
+
+
+def test_scan_sequence_and_listing():
+    """
+    Check created scans are added in order and listed correctly
+    """
+    _clear_scan_dir()
+    scan_dir_manager = ScanDirectoryManager(BASE_SCAN_DIR)
+    # Make 4 scans
+    scan_dir_manager.new_scan_dir("fake_scan")
+    scan_dir_manager.new_scan_dir("fake_scan")
+    scan_dir_manager.new_scan_dir("fake_scan")
+    scan_dir_manager.new_scan_dir("fake_scan")
+
+    # Check they exist and are numbered sequentially
+    all_scans = scan_dir_manager.all_scans
+    assert len(set(all_scans)) == 4
+    assert "fake_scan_0001" in all_scans
+    assert "fake_scan_0002" in all_scans
+    assert "fake_scan_0003" in all_scans
+    assert "fake_scan_0004" in all_scans
+
+    # Check scan data can be read for all of them
+    # (more detailed scan_info tests below)
+    all_scan_info = scan_dir_manager.all_scans_info()
+    for scan_info in all_scan_info:
+        assert isinstance(scan_info, ScanInfo)
+        assert scan_info.name.startswith("fake_scan_000")
+        assert scan_info.number_of_images == 0
+
+
+def test_scan_name_non_sequential():
+    """
+    Check created scans is the correct name if the directories
+    are not sequential
+    """
+    _clear_scan_dir()
+    os.makedirs(os.path.join(BASE_SCAN_DIR, "fake_scan_0001"))
+    os.makedirs(os.path.join(BASE_SCAN_DIR, "fake_scan_0002"))
+    os.makedirs(os.path.join(BASE_SCAN_DIR, "fake_scan_0003"))
+    os.makedirs(os.path.join(BASE_SCAN_DIR, "fake_scan_0005"))
+    os.makedirs(os.path.join(BASE_SCAN_DIR, "fake_scan_0007"))
+    os.makedirs(os.path.join(BASE_SCAN_DIR, "fake_scan_0011"))
+    scan_dir_manager = ScanDirectoryManager(BASE_SCAN_DIR)
+
+    scan_dir = scan_dir_manager.new_scan_dir("fake_scan")
+    assert scan_dir.name == "fake_scan_0012"
+
+    all_scans = scan_dir_manager.all_scans
+    assert len(set(all_scans)) == 7
+    assert "fake_scan_0001" in all_scans
+    assert "fake_scan_0002" in all_scans
+    assert "fake_scan_0003" in all_scans
+    assert "fake_scan_0005" in all_scans
+    assert "fake_scan_0007" in all_scans
+    assert "fake_scan_0011" in all_scans
+    assert "fake_scan_0012" in all_scans
+
+
+def test_all_scan_names_taken():
+    """
+    If the next sequential scan name needs more than 4 digits check error is thrown.
+    """
+    _clear_scan_dir()
+    os.makedirs(os.path.join(BASE_SCAN_DIR, "fake_scan_9999"))
+    scan_dir_manager = ScanDirectoryManager(BASE_SCAN_DIR)
+    with pytest.raises(FileExistsError):
+        scan_dir_manager.new_scan_dir("fake_scan")
+
+
+def test_no_scan_names_given():
+    """
+    Check correct default scan name is used if empty string is given
+    """
+    _clear_scan_dir()
+    scan_dir_manager = ScanDirectoryManager(BASE_SCAN_DIR)
+    scan_dir = scan_dir_manager.new_scan_dir("")
+    assert scan_dir.name == "scan_0001"
+
+
+def test_scan_info():
+    """Test the scan info is correct even using fake scan data"""
+    _clear_scan_dir()
+    scan_dir_manager = ScanDirectoryManager(BASE_SCAN_DIR)
+    scan_dir = scan_dir_manager.new_scan_dir("fake_scan")
+
+    for i in range(17):
+        _add_fake_image(scan_dir)
+    info = scan_dir.scan_info()
+    now = time.time()
+
+    assert info.name == "fake_scan_0001"
+    # Created and modified in the last 5 seconds
+    assert now - 5 < info.created < now
+    assert now - 5 < info.modified < now
+    assert info.number_of_images == 17
+    assert not info.stitch_available
+    assert info.dzi is None
+
+    # Add a fake scan and check this is recognised as a stitch not a scan image
+    _add_fake_file(scan_dir, "fake_scan_0001_stitched.jpg", in_im_dir=True)
+    info = scan_dir.scan_info()
+    assert info.number_of_images == 17
+    assert info.stitch_available
+
+
+def test_empty_scan_info():
+    """Test the scan info is correct even if the scan is empty"""
+    _clear_scan_dir()
+    scan_dir_manager = ScanDirectoryManager(BASE_SCAN_DIR)
+    scan_dir = scan_dir_manager.new_scan_dir("fake_scan")
+
+    info = scan_dir.scan_info()
+    now = time.time()
+
+    assert info.name == "fake_scan_0001"
+    # Created and modified in the last 5 seconds
+    assert now - 5 < info.created < now
+    assert now - 5 < info.modified < now
+    assert info.number_of_images == 0
+    assert not info.stitch_available
+    assert info.dzi is None
+
+
+def test_zipping_scan_data():
+    """Test zipping the scan images with fake image data"""
+
+    # Run twice, once calling the ScanDirectory directly,
+    # Once calling the ScanDirectoryManager
+    for caller in ["scan_dir", "manager"]:
+        _clear_scan_dir()
+        scan_dir_manager = ScanDirectoryManager(BASE_SCAN_DIR)
+        scan_dir = scan_dir_manager.new_scan_dir("fake_scan")
+
+        # Create 21 fake scan images, a fake stitch, and a fake zip
+        for i in range(21):
+            _add_fake_image(scan_dir)
+        _add_fake_file(scan_dir, "fake_scan_0001_stitched.jpg", in_im_dir=True)
+        _add_fake_file(scan_dir, "zipfile.zip")
+
+        # zip the directory without setting as the final version. It should only
+        # zip the 21 scan images
+        if caller == "scan_dir":
+            zip_fname = scan_dir.zip_files()
+        else:
+            zip_fname = scan_dir_manager.zip_scan("fake_scan_0001")
+        zip_files = get_files_in_zip(zip_fname)
+        assert len(set(zip_files)) == 21
+
+        # Zip again with final version on and there should be 22 images
+        if caller == "scan_dir":
+            scan_dir.zip_files(final_version=True)
+        else:
+            scan_dir_manager.zip_scan("fake_scan_0001", final_version=True)
+        zip_files = get_files_in_zip(zip_fname)
+        assert len(set(get_files_in_zip(zip_fname))) == 22
+        # Check the zips are not in the zip
+        for file in zip_files:
+            assert not file.endswith(".zip")
+
+
+def test_creating_scan_dir_for_missing_scan():
+    """Check creating ScanDirectory object for a dir that doesn't exist fails."""
+    _clear_scan_dir()
+    with pytest.raises(FileNotFoundError):
+        ScanDirectory(BASE_SCAN_DIR, "not_real_0001")
+
+
+def test_none_returned_for_missing_images_dir():
+    """None should be returned for image dir path if images dir does not exist.
+
+    By default images directories are created at the same time the scan directory
+    is created. However, edge cases such as problems in deletions, microscopes
+    with older scans on, etc can cause and empty scan directory, so it is handled
+    explicitly.
+    """
+    _clear_scan_dir()
+    os.makedirs(os.path.join(BASE_SCAN_DIR, "fake_scan_0001"))
+    scan_dir = ScanDirectory(BASE_SCAN_DIR, "fake_scan_0001")
+    assert scan_dir.images_dir is None
+    # Also check that get scan files returns and empty list
+    assert scan_dir.get_scan_files() == []
+
+
+DiskUsage = namedtuple("DiskUsage", ["total", "used", "free"])
+
+
+@pytest.mark.parametrize("free_space", [500_000_001, 700_000_000, 5_000_000_000])
+def test_disk_not_full(mocker, free_space):
+    """Check no error thrown if disk has over 500MB of space"""
+    total_space = 16_000_000_000
+    # Mock the disk_usage
+    mocker.patch(
+        "shutil.disk_usage",
+        return_value=DiskUsage(
+            total=total_space, used=total_space - free_space, free=free_space
+        ),
+    )
+
+    scan_dir_manager = ScanDirectoryManager(BASE_SCAN_DIR)
+    scan_dir_manager.check_free_disk_space()
+
+
+@pytest.mark.parametrize("free_space", [100_000_000, 499_999_999])
+def test_disk_full(mocker, free_space):
+    """Check error thrown if disk has under 500MB of space"""
+    total_space = 16_000_000_000
+    # Mock the disk_usage
+    mocker.patch(
+        "shutil.disk_usage",
+        return_value=DiskUsage(
+            total=total_space, used=total_space - free_space, free=free_space
+        ),
+    )
+
+    scan_dir_manager = ScanDirectoryManager(BASE_SCAN_DIR)
+    with pytest.raises(NotEnoughFreeSpaceError):
+        scan_dir_manager.check_free_disk_space()
diff --git a/tests/test_smart_scan.py b/tests/test_smart_scan.py
new file mode 100644
index 00000000..8c8e791e
--- /dev/null
+++ b/tests/test_smart_scan.py
@@ -0,0 +1,265 @@
+"""
+Test the SmartScanThing *without* connecting it to a LabThings Server.
+
+By testing without connecting to the LabThings server it is possible to
+directly poll any properties and to start any methods.
+
+Any methods with LabThings dependency injections will require dependencies
+to be passed in manually. Rather than passing in real LabThings clients
+it is possible to create test objects that mock these clients. Thus, entirely
+isolating one Thing for testing, at the expense of needing to create detailed
+mock objects.
+
+For these tests to reliably represent real behaviour the mock Things will need to
+be tested for matching signatures with dynamically generated clients.
+"""
+
+from typing import Callable, Optional
+import tempfile
+import os
+import shutil
+import logging
+
+from fastapi import HTTPException
+import pytest
+
+from openflexure_microscope_server.things.smart_scan import (
+    SmartScanThing,
+    ScanNotRunningError,
+)
+
+from .mock_things.mock_csm import MockCSMThing
+from .mock_things.mock_autofocus import MockAutoFocusThing
+from .mock_things.mock_stage import MockStageThing
+from .mock_things.mock_background_detect import MockBackgoundDetectThing
+
+# A global logger to pass in as an Invocation Logger
+LOGGER = logging.getLogger("mock-invocation_logger")
+
+# Use our own dir in the root temp dir not a dynamically generated one so we
+# have some control of when it is deleted
+SCAN_DIR = os.path.join(tempfile.gettempdir(), "scans")
+
+
+def _clear_scan_dir() -> None:
+    """Delete the scan dir"""
+    if os.path.exists(SCAN_DIR):
+        shutil.rmtree(SCAN_DIR)
+
+
+@pytest.fixture
+def smart_scan_thing():
+    """Return a smart scan thing as a fixture"""
+    return SmartScanThing(SCAN_DIR)
+
+
+def test_initial_properties(smart_scan_thing):
+    """Check the initial values of properties.
+
+    Test properties of SmartScanThing are available without a ThingServer
+    and return expected default values.
+    """
+    assert smart_scan_thing._scan_dir_manager.base_dir == SCAN_DIR
+    assert smart_scan_thing.latest_scan_name is None
+
+
+def test_inaccessible_scan_methods(smart_scan_thing):
+    """The @_scan_running decorator should make some methods
+    inaccessible unless a scan is running"""
+    with pytest.raises(ScanNotRunningError):
+        smart_scan_thing._run_scan()
+    with pytest.raises(ScanNotRunningError):
+        smart_scan_thing._manage_stitching_threads()
+
+
+def test_private_delete_scan(smart_scan_thing, caplog):
+    """Test the private _delete_scan method deletes directories or warns if it can't"""
+
+    _clear_scan_dir()
+    with caplog.at_level(logging.INFO):
+        fake_scan_name = "fake_scan_0001"
+        fake_scan_path = os.path.join(SCAN_DIR, fake_scan_name)
+
+        # Make the outer scan dir, but not the one to delete
+        os.makedirs(SCAN_DIR)
+        # Attempt to delete the fake scan. Expect it to fail and provide a warning
+        deleted = smart_scan_thing._delete_scan(fake_scan_name, LOGGER)
+        assert not deleted
+        assert len(caplog.records) == 1
+        assert caplog.records[0].levelname == "WARNING"
+        assert caplog.records[0].name == "mock-invocation_logger"
+
+        # Make a dir for the fake scan and delete it.
+        os.makedirs(fake_scan_path)
+        assert os.path.exists(fake_scan_path)
+        deleted = smart_scan_thing._delete_scan(fake_scan_name, LOGGER)
+        assert not os.path.exists(fake_scan_path)
+        assert deleted
+        # Check no extra logs generated
+        assert len(caplog.records) == 1
+
+
+def test_public_delete_scan(smart_scan_thing, caplog):
+    """Test the delete_scan API call deletes directories or warns if it can't"""
+
+    _clear_scan_dir()
+    with caplog.at_level(logging.INFO):
+        fake_scan_name = "fake_scan_0001"
+        fake_scan_path = os.path.join(SCAN_DIR, fake_scan_name)
+
+        # Make the outer scan dir, but not the one to delete
+        os.makedirs(SCAN_DIR)
+
+        # Attempt to delete the fake scan. Expect it to fail
+    with pytest.raises(HTTPException) as exc_info:
+        smart_scan_thing.delete_scan(fake_scan_name, LOGGER)
+        # Should raise a 400 error if the scan doesn't exist, not a 404 as the server
+        # was not expecting to receive the scan files
+        assert exc_info.value.status_code == 400
+        assert len(caplog.records) == 1
+        assert caplog.records[0].levelname == "WARNING"
+        assert caplog.records[0].name == "mock-invocation_logger"
+
+        # Make a dir for the fake scan and delete it.
+        os.makedirs(fake_scan_path)
+        assert os.path.exists(fake_scan_path)
+        smart_scan_thing.delete_scan(fake_scan_name, LOGGER)
+        assert not os.path.exists(fake_scan_path)
+        # Check no extra logs generated
+        assert len(caplog.records) == 1
+
+
+def test_delete_all_scans(smart_scan_thing, caplog):
+    """Check the delete_all_scan API really does delete all the scans."""
+    _clear_scan_dir()
+    with caplog.at_level(logging.INFO):
+        fake_scan_names = [
+            "fake_scan_0001",
+            "fake_scan_0002",
+            "fake_scan_0003",
+            "fake_scan_0004",
+        ]
+        for fake_scan_name in fake_scan_names:
+            fake_scan_path = os.path.join(SCAN_DIR, fake_scan_name)
+            os.makedirs(fake_scan_path)
+            assert os.path.exists(fake_scan_path)
+        smart_scan_thing.delete_all_scans(LOGGER)
+        for fake_scan_name in fake_scan_names:
+            fake_scan_path = os.path.join(SCAN_DIR, fake_scan_name)
+            assert not os.path.exists(fake_scan_path)
+        # No logs generated
+        assert len(caplog.records) == 0
+
+
+def _run_only_outer_scan(adjust_inital_state: Optional[Callable] = None):
+    """
+    Create a subclass of SmartScanThing to mock _run_scan and run sample_scan
+
+    This should do all the set up for a scan, move into the mocked
+    _run_scan method where this can be tested. Once this is done
+    the final scan behaviour can be tested too.
+
+    adjust_initial_state is a callable which accepts the mocked smart scan thing
+    as the only variable. It can be used to adjust the initial state of the test
+
+
+    This seems hard to do with a fixture so it is being done with a private
+    function
+    """
+
+    # cancel handle shouldn't be used. Set to arbitrary value for checking
+    cancel_mock = 1  # not called
+    af_mock = MockAutoFocusThing()
+    stage_mock = MockStageThing()
+    cam_mock = 4  # not called
+    meta_mock = 5  # not called
+    csm_mock = MockCSMThing()
+    bkgrnd_det_mock = MockBackgoundDetectThing()
+
+    class MockedSmartScanThing(SmartScanThing):
+        """
+        This is a subclass of SmartScanThing with a mocked method and
+        mocked thing_settings.
+        """
+
+        # Counter for checking functions were called
+        mock_call_count = {"_run_scan": 0}
+
+        # Mock thing settings as a dictionary
+        thing_settings = {"skip_background": True}
+
+        def _run_scan(self):
+            self.mock_call_count["_run_scan"] += 1
+
+            """Check scan vars are set up as expected"""
+            assert not self._scan_lock.acquire(timeout=0.1)
+            assert self._cancel is cancel_mock
+            assert self._scan_logger is LOGGER
+            assert self._autofocus is af_mock
+            assert self._stage is stage_mock
+            assert self._cam is cam_mock
+            assert self._metadata_getter is meta_mock
+            assert self._csm is csm_mock
+            assert self._background_detect is bkgrnd_det_mock
+            assert self._capture_thread is None
+            assert self._scan_images_taken == 0
+
+    # mock smart scan thing
+    mock_ss_thing = MockedSmartScanThing(SCAN_DIR)
+
+    if adjust_inital_state is not None:
+        adjust_inital_state(mock_ss_thing)
+
+    exec_info = None
+    try:
+        mock_ss_thing.sample_scan(
+            cancel=cancel_mock,  # Shouldn't be used, can be checked
+            logger=LOGGER,
+            autofocus=af_mock,
+            stage=stage_mock,
+            cam=cam_mock,
+            metadata_getter=meta_mock,
+            csm=csm_mock,
+            background_detect=bkgrnd_det_mock,
+            scan_name="FooBar",
+        )
+    except Exception as e:
+        exec_info = e
+
+    assert mock_ss_thing._scan_lock.acquire(timeout=0.1)
+    mock_ss_thing._scan_lock.release()
+    assert mock_ss_thing._cancel is None
+    assert mock_ss_thing._scan_logger is None
+    assert mock_ss_thing._autofocus is None
+    assert mock_ss_thing._stage is None
+    assert mock_ss_thing._cam is None
+    assert mock_ss_thing._metadata_getter is None
+    assert mock_ss_thing._csm is None
+    assert mock_ss_thing._background_detect is None
+    assert mock_ss_thing._capture_thread is None
+    assert mock_ss_thing._scan_images_taken is None
+
+    # Return the mock thing for further state testing, and the
+    # exec_info of any uncaught exeptions that were raised
+    return mock_ss_thing, exec_info
+
+
+def test_outer_scan():
+    """Test setup and teardown of the scan."""
+    mock_ss_thing, exec_info = _run_only_outer_scan()
+    assert exec_info is None
+    # Checked the mocked _run_scan was run exactly once
+    assert mock_ss_thing.mock_call_count["_run_scan"] == 1
+
+
+def test_outer_scan_wo_sample_skip():
+    """Test setup and teardown of the scan."""
+
+    def _set_skip_background(mock_ss_thing):
+        mock_ss_thing.thing_settings["skip_background"] = False
+
+    mock_ss_thing, exec_info = _run_only_outer_scan(_set_skip_background)
+
+    assert exec_info is None
+    # Checked the mocked _run_scan was run exactly once
+    assert mock_ss_thing.mock_call_count["_run_scan"] == 1
diff --git a/tests/test_stack.py b/tests/test_stack.py
index c9fad430..e9295601 100644
--- a/tests/test_stack.py
+++ b/tests/test_stack.py
@@ -17,7 +17,7 @@ from openflexure_microscope_server.things.autofocus import (
     _get_capture_by_id,
     _get_capture_index_by_id,
 )
-from openflexure_microscope_server.things.smart_scan import IMAGE_REGEX
+from openflexure_microscope_server.scan_directories import IMAGE_REGEX
 
 RANDOM_GENERATOR = np.random.default_rng()
 
diff --git a/webapp/src/components/tabContentComponents/scanListContent.vue b/webapp/src/components/tabContentComponents/scanListContent.vue
index 293b9d0c..79741558 100644
--- a/webapp/src/components/tabContentComponents/scanListContent.vue
+++ b/webapp/src/components/tabContentComponents/scanListContent.vue
@@ -240,8 +240,6 @@ export default {
           this.scans = scans;
         }
         scans.forEach(scan => {
-          scan.modified = Date.parse(scan.modified);
-          scan.created = Date.parse(scan.created);
           scan.can_stitch = !scan.stitch_available && scan.number_of_images > 3;
         });
         scans.sort((a, b) => {
@@ -255,7 +253,9 @@ export default {
       }
     },
     formatDate(timestamp) {
-      let d = new Date(timestamp);
+      // Multiply by 1000 as JS uses ms not s
+      let d = new Date(timestamp*1000);
+      // Convert to a string in a very javascript way!
       let yyyy = d.getFullYear();
       let mm = d.getMonth() + 1;
       let dd = d.getDate();