Not really Sheffield but Byron (he's a good saddle fitter as well) from Retford saddlery is often in Sheffield and will pick saddle up,take it away to reflock/alter/ whatever and post it back to you (i did this,postage not much and arrives in a massive box that kids played in for ages!) or you collect or he drops back off next time he's around. Google Retford saddlery &ring him up.
He will look at it on horse first,stationary (and ridden if necess.) Not sure,depends on what needs doing but when I had him out to re-check fit of my saddle(horse had changed shape) it was £30 and can't remember exactly re-flock price,sorry He's very nice-just give him a ring. He will not tell u something needs doing if it doesn't.