My friend in London recommended a couple of game-friendly pubs:
St Christopher's, London Bridge: Used by his RPG meetup regularly, but apparently might be a bit busy on a Saturday
White Mustache, Camden: "Really cool beer selection, and they're very game-friendly -- if you phoned ahead, you could probably reserve a table that's slightly separated from the rest of the bar"
A pub might not be ideal from the point of view of Actual Fighting Games on a computer/console, but those are some suggestions for now. Personally my terrible reflexes and lack of knowledge mean that I'd be 100% happy with FSFG on a laptop, and would be just fine even with only physical game stuff.