we have parked up for the night in london once or twice in residential areas, golders green area or the hendon area just off the m1 staples corner area , and found it ok .but we lived in london for a while and sort of know our way round there if get my drift ,there are quite a few no go areas during the day not to mention night time . if you will be there for a few nights try to find a pub on the outskirts that will let you stay on the car park best bet , if not then an industrial estate preferably in company with some overnighting lorries. we used to live at chadwell heath near barking just off the north circular there were quite a few places round that area and it was a pretty ok place but that was a few years ago now , london and its outskirts is not the place realy to just turn up and park you realy need to get further out for safety