That house is in the very heart of Plumstead, no where near Blackheath!
There are some truely beautiful houses (with potential, obviously!) in that area and it is a real shame that the local area is so rubbish. It's one of those places that has just been left to rot, whist some of the neighbouring areas have had some regeneration.
I do like the house, but I'm seeing through the decor tbh. I don't think the garden is that small. I think it just needs an awful lot of pruning. I reckon you could get another couple of feet on the sides, if you chopped down a bit of greenery!