Close for a wild guess, Bill. You're in the right area but you're a bit too far south.

isn't that in Camden?

Kelly St is on the border of Kentish Town and Camden but this is a bit north of there.

South End Green-ish?

Not S. End Green. You've gone too far now. It is closer to Kelly St.
I can see you're getting all excited about the new buses on the 24 route. By way of a clue, the 24 has turned off before it reaches here but you would pass on the 134...

Yes, anoraks that we (or at least, me) are, studying the tfl bus route maps. I think this might be Mem's Café in Kentish Town Road, looking towards Fortress Road.

Mem's cafe it is indeed. I just noticed the Amy Winehouse paintings (there's another one I'll post a pic of soon) when I was passing the other day. I was chatting to the cafe owner and it was him who painted them. I'd never really taken much notice of the cafe until the other day but it seems a really nice place so I must pop in for a coffee soon.