where are they?

y'know what i'm talking about here. probably a couple of middle-aged men behind the counter, might sell a few home brew kits and ingredients. but what (hopefully) they also have is a vast array of beers, ales, bitters, wheat beers, lagers, trappist beers , porters, stouts, etc etc etc, from these shores and further afield.

i know there's a few beer conisseurs on these here boards - where in london (preferably central, east or at a push north) are they??