Some tips ...

The Anchor, Lewisham every Thursday evening 9.30ish

The Duke Of Edinburgh, Lee Green every Wednesday evening 9.30ish

The Hollydale, Nunhead last Sunday every month 4-7ish

The Woodman, Lee High Road every Sunday evening 9.00ish (this one is slightly harder than the others to "break into", given that the players are a) of a very high standard and b) have been playing together for some considerable time. However worth checking out.