I'd love to forage, but I think the only thing near me is likely to be seaweed!
I live in the North of Scotland, tree are few (apart from Forestry land - which has prohibited access), and I've not seen any fruit trees of any kind. I can't even garden here - I'm maybe 1000 yards from the sea, and the winds are fierce. I brought lots of plants with me, but not many survived the latter part of the winter (we arrived here at the beginning of February). I haven't seen even Brambles, as yet!
To think that London, or anywhere else for that matter, does not belong to any one demographic