As Geejay has already mentioned - Sound Control in the basement of the Virgin Megastore, corner of Oxford st. and Tottenham Court rd. is always worth a visit. I know they get a lot of stick for not be very knowledgeable about the basses, however they have a very decent stock and you could stay there all day playing different basses and nobody would care/notice. From memory they have all the Musicman range, including the H, HH, HJ ones, big selection of Fenders, Yamaha, Spector including the high end US made ones, plus various other makes. Amp include Ashdown, Trace and Mesa In my experience they also price match with any Internet price you quote. Just don't expect in dept advise....