About 20 years ago I lived in Croydon, when I moved in the flat above was being used by druggies, they never bothered me but I suspected something was happening with all the late night comings and goings, they got wind that they were about to be busted and moved out sharpish, the flat was rented out again, this time it was used as a massage parlour, I didn't find out until it was sold, the owner lived in Scotland, so you never know what is happening on the street where you live