Don't know about Brixton, but there's a good club in Tooting, not far away, and easily accessible by any bus going to Tooting Broadway. Court Sessions is every Friday at St. Boniface Social Club, 185 Mitcham Road, SW17.

I can recommend Broadstairs Folk Week in Kent, 5th-12th August - lots going on whatever your taste in folk-type music - and beyond! - and whether you want to play, sing, listen or whatever.