you could try Husbands Saddlery in Ryarsh, he's the only saddler I would recommend in Kent and have seen most of them. Peter is a decent honest man and hard to find.
Andrew Reilley is based in Hadlow Down and adjusts my Wintec for me. I think he does Thorowogoods aswell. You should be able to find his number on google. If not PM me and I will find it out.