I've used Malvern Saddle Company before - sorry, can never remember the guys name - and was very pleased. Someone else asked a similar question on here a while ago and I mentioned him and a few others had also had a good experience of him.
You've also got Laurence from Stroud Saddlery but I hear you have to wait ages for him as he is so popular, otherwise there is also Maurice from Colne Saddlery, again used him too and he was good.
Julia Duffin in Marlborough is a very good fitter/Master Saddler and sells new and secondhand saddles. Honest lady too, will only sell you what you really need, if you need it.