Awesome 531 is too flexy for me

having thought a bit more about this, I don't think BB problems have been ruled out (?) because a knackered BB doesn't always show unless it's under load. Quite often you can spin a BB, rock it up and down and all that and it will appear fine, only when you climb a hill or put in a hard standing start will it grumble. If it's a year old cheap sealed BB, then change it. if it's an even older loose ball and axle job then change it.

as always, this is a process of elimination, usually if I ride the bike in question I can isolate the problem better than shooting in the dark on an internet forum.

The BB is a 3 month old campag veloce, installed by Mercian when they renovated the frame.
Someone at Brixton Cycles did take it for a test ride after it was checked over, don't know if this was the mechanic or not. Its pretty flat around that area though so not sure if they would have encountered the problem as I seem to.

RPM, if thats an offer I would be very grateful! Where are you in London?

I've just had a quick go at respacing the rear hub but it seems I need 17mm cone spanners and mine only go up to 16mm. Had a go with adjustable spanners but no luck so far!