I went to Brothers next Harvey's on the High Street- they're expensive but I had a trainee do mine which made it under £20 and she did a really good job.
I have a friend who likes the barbers in the Covered Market, he claims that whenever you go in, all the barbers stop working, turn round and say hello! This seems to be his main reason for going, but his hair is usually OK so they can't be too bad.