A building was mapped there in 2015 as part of https://www.openstreetmap.org/changeset/34342795#map=15/51.5068/-0.0184 claiming mapbox satellite as source. The current mapbox satellite does not show a building there but bing streetside is showing what may be have been a temporary portacabin used by builders of the adjacent estate. I've provisionally deleted that "building" and suggest the area be properly surveyed.