A previous thread on this topic:
http://www.nappyvalleynet.com/mums/sear ... ee+surgeon
I have used Jonathan Lewis as well over the years, and would always call him, local, quick to respond, knows his stuff, reasonable prices, professional and a nice guy.
I also found it true that once you start pruning/reducing/whatever the right term is they grow so fast, you then get drawn into a cycle of maintenance, and therefore cost, so also something to discuss with whoever you find.