I have recently discovered Yelp.co.uk and you can write a review on bike shops, amongst other things. People have been writing reviews on Cycle Surgery, Evans etc.. please do write a review and we can see if we are being ripped off or not. It is important to read about the good ones too.
Watch out for the really good reviews as it could have been written by management. It is too easy to set up a fake review on here though.