Thanks for surveying the area. I've checked post address database and can't see houses with numbers 1/6, 2/6 and etc. Basically if estate doesn't have house number, only units (flats), it would be better to survey flats numbers for each house. I've made a guesstimate by splitting 66 flats into 6 buildings evenly. Let me know if you have any additional info regarding the estate. 