In lincs there's Robinsons, at Billinghay, google it and they're number will come up, it's Nigel that comes out, he's really nice and knows his stuff, he will re flock it from his van too while he is with you.
Good luck.
Kate x
I too can recommend Nigel from Robinsons at billinghay.
We bought a new pony about 8 wks ago and Nigel came to fit a saddle. He spent a good 5 mins just looking at the pony, before feeling him all over and telling me he's left-handed (the pony that is!) which was correct. Anyway, he then tried a few saddles on him before settling for one (which was not the most expensive he had brought with him!). He checked the saddle while my daughter was riding too, not just on a stationary pony.
There's also Debbie Richardson (I think) advertises in the back of Equestrian Life. Or Chandlers have a saddle fitter but only new saddles, no second hand ones.