The odd thing (from my POV) is that London's biggest Bulgarian community is in Haringey, particularly between Wood Green and Turnpike Lane. But while there are more Hungarian WGs than you can shake a stick at, and quite a few Romanians in that area, the Bulgarians seem to be in short supply.
Mind you, Bulgarians are shrewd (if not to say wily) business people, so maybe they've worked out that there's a more lucrative area in London to ply their trade. I just wish I knew where that was!