Hi Kieran,
Deleting an offline area from Collector should create a call to REST to delete the replica the next time a connection is established. Sometimes you may be in a state where you cannot delete the map from the device because the device is unavailable, locked, or any other reason. As long as you have already synced any changes in the data or recovered the database directly you should be safe to manually delete any replicas or versions.
Based on your description of your workflow, it sounds like you may be better suited using Explorer for ArcGIS as you are not making field edits. Explorer also allows for Offline maps and GPS locations (no external GPS support).
Regards,
Colin
Regards,
Colin