OS is increasingly making available data under public open licences. I believe data under open government licence should be compatible with OSM, as it's pretty

OS is increasingly making available data under public open licences. I believe data under open government licence should be compatible with OSM, as it's pretty permissive. If you combine a few different datasets you can build a pretty good picture https://www.ordnancesurvey.co.uk/business-government/products?Product%20type=0/154/173/175 https://www.ordnancesurvey.co.uk/business-government/product... The UPRN dataset gives you a point coordinate for each property. The Zoomstack map gives building level vectors, I believe (if it isn't Zoomstack, it's one of the other free and open ones), and is pretty usable in qgis and other tools.