diff --git a/src/openflexure_microscope_server/things/smart_scan.py b/src/openflexure_microscope_server/things/smart_scan.py
index d2bd4921..559aea47 100644
--- a/src/openflexure_microscope_server/things/smart_scan.py
+++ b/src/openflexure_microscope_server/things/smart_scan.py
@@ -702,7 +702,7 @@ class SmartScanThing(lt.Thing):
         """
         scan_data_dict = self._scan_dir_manager.get_scan_data_dict(scan_name)
         if scan_data_dict is None:
-            logger.warning("Couldn't read scan data it may be missing or corrupt.")
+            logger.warning("Couldn't read scan data - it may be missing or corrupt.")
         final_stitcher = stitching.FinalStitcher(
             self._scan_dir_manager.img_dir_for(scan_name),
             logger=logger,
@@ -712,6 +712,7 @@ class SmartScanThing(lt.Thing):
             scan_data_dict=scan_data_dict,
         )
         try:
+            # start the final stitch, providing the cancel hook to allow aborting
             final_stitcher.start(cancel)
         except lt.exceptions.InvocationCancelledError:
             # Sleep for 1 second just to allow invocation logs to pass to user.
diff --git a/src/openflexure_microscope_server/utilities.py b/src/openflexure_microscope_server/utilities.py
index 07bc4fea..bbad56f9 100644
--- a/src/openflexure_microscope_server/utilities.py
+++ b/src/openflexure_microscope_server/utilities.py
@@ -128,8 +128,11 @@ def _wrap_and_catch_errors(target, error_buffer, *args, **kwargs):
 
 
 # Compiled regular expressions for unsafe characters
+# Matches anything that isn't a-z, A-Z, 0-9, _, ., -, :, /, \
 _WINDOWS_UNSAFE_PATTERN = re.compile(r"[^a-zA-Z0-9_.\-:/\\]")
+# Matches anything that isn't a-z, A-Z, 0-9, _, ., -, \
 _POSIX_UNSAFE_PATTERN = re.compile(r"[^a-zA-Z0-9_.\-/]")
+# Matches anything that isn't a-z, A-Z, 0-9, _, ., -
 _NAME_UNSAFE_PATTERN = re.compile(r"[^a-zA-Z0-9_.\-]")