Just read this thread. I noticed a man/boy matching this description in Garthorne Road this morning around 9 am.

He was wearing a black nylon hooded tracksuit and a black wool cap.
I'd have estimated his age at between late teens to early twenties.
He was standing in the middle of the road staring intently up at the bedroom window of one of the houses. Quite blatant and not at all furtive.

I gave him a close look because I thought that his behaviour looked a bit dodgy. He noticed me clocking him and began to walk off down the middle of the road heading in the direction of Forest Hill.