This is what it's all about - small portions, home-made food, disco music - and plenty of it. I had a crab open sandwich draped with just one seductive marinated white anchovy and a blob of mustard mayo for £3 at Donastia Social Club's Basque food wagon at Kerb. Next door was (at last!) a stall selling a good selection (3) of interesting fresh fruit drinks - melon, raspberry lemonade and plum juice sodas at £2.50 from Square Root London.