Hiya, if you’re going to add lots of buildings, please make sure the aerial imagery is lined up with the OSMUK Cadastral Parcels before starting. That eliminates any imagery offset error, which varies about 0-3m in both axes across the country. In this bit of Kendal it looks like it’s about 0.09,-0.83m for the Bing imagery, which means these buildings are all about 1m misaligned from ground truth. Thanks :)