Mark Fisher is brilliant - I've tried most of the local fitters, but Mark def gets my vote. If you have transport take your horse to him, if not, he does come out ot Norfolk but you may have to wait a while.
You can call Granvilles Saddlery in Wymondham. They will happily give you the number for a local saddle fitter.
Was a few years ago now but the saddle fitter i had was called Jane. She was really helpful and totally honest. She has a large variety of second hand leather saddles and came out for free to check how i was getting on once i had brought a saddle a few weeks later.
Jane English is the one Granvilles use but she's on maternity leave at the moment. I really rate Alison from Mill Saddlery (same place as Liz Leggot - I've heard she's very good too). Alison fitted a S/H dressage saddle to my IDxTB who is really a problem shape, and I'm really pleased with the result.