A few links that may assist...
Ain't Nothin' But, 20 Kingly St W1 (Behind Hamley's in Regent St).
The 100 Club 100 Oxford St.
12 Bar Club Denmark St, where the guitar shops are - can be a bit indie-tastic.
Ronnie Scott's- mostly Jazz, but Pee Wee Ellis is coming up.
Blues In London - Does what it says on the tin.
If you're in town on Wednesday & feel adventurous, hop on the Central Line to the
Coach & Horses Blues Jam in sunny Leyton. Next week are the excellent Paul Garner ably abetted by ace Hammond player Claudio Corona. If you can make it & fancy a blow, you're more than welcome to borrow my fretless.
Pete.