Ah! The Croydon Folksingers Club. An early incarnation at The Swan & Sugarloaf was my regular and the first place I dared to sing out.
Those were the days.
There was another club nearby at Parsons Pightle Rugby Club on Mondays (I think) which was very good.
Used to go to The Singers Club fairly regularly and had a few good natured rows with Ewan about singing from your own tradition as my tradition was mainly contemporary stuff.