In a world where younger generations seem uninterested in the strong musical links which tie their favourite artists to anything pre-1995 (Charli XCX to Bonnie Raitt, via Justin Vernon, say) independent south London venues like the Effra Hall Tavern, The Windmill, The Swan, Jam Circus, The Crypt, Oliver’s and the White Lion champion a scene dedicated to connecting revellers, true music lovers, to that past.