In reply to sankster:
I've just bought a pair of B2s. I'll probably get shouted down for saying this but I went round several independent climbing shops (which I normally like to support) and I just wasn't getting good enough advice. I then went to Cotswold (Keswick) and the guy was fantastic - he obviously had had specific training on feet/boots.
......so I suppose my point is, try to find somewhere where the staff have had specific training on boots, which might mean choosing a bigger shop like the branches around Covent Garden. If you have funny feet, some people speak highly about moulded insoles, but I've never tried them.