... picture shape tiles without any noticeable effect on zoom and pan speeds. That certainly wouldn't be the case if this was a single large captured screenshot of several dozen MB. The BGS shapes file can be saved in the usual way, it is only necessary to load the map tiles from the OSM server once. It's much easier to work with the picture shape borders turned off. A rectangle shape is also drawn showing the requested area -- Templot loads only full tiles, so these overlap the requested area a little way: 2_222110_340000003.png© OpenStreetMap contributors Here I have started overlaying a template on the map: 2_222110_540000000.png© OpenStreetMap contributors This is Bewdley on the Severn Valley Railway: 2_222110_340000002.png© OpenStreetMap contributors The disadvantage with OSM is that it is not always as accurate as OS maps. But of course anyone can go on there and edit it, so if the map doesn't have all the information you need you can add or amend it. Usually that means tracing from aerial imagery, but you can also cross-fade from OSM to the historic 25" ...