I only really know of three places, which are all in Clapham:
Infernos - cheesy as fuck, a bit low class, but some HBs there and it's large so you'll have plenty of sets to open and practice. It's a bit of a meat market.
Clapham Grand - pretty much the same as Infernos!
The White House - lots of HBs but the times I've been there they've been a bit stuck up and full of themselves and I've had no luck (though I'm an AFC). My 6'3" good looking natural SPAM has picked up there a few times though, so that could just be me.
I also heard of people picking up in the Clapham North pub. That's quite good on a weekend, I've number closed in there on a Sunday - never made it to day 2 though

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