Hi ridingmilly, welcome to Western! Not knowing anything about your saddle or whether it's got leather or synthetic fenders, I can only give you details of various UK western tack vendors and general info.
To find out more about Western in the UK, look at:
- forum with general info and links to most UK Western organisations, horse breeders, retailers, trainers etc.
- the Western Equestrian Society
- AQHA's UK affiliate association
- Pullman Western Store in UK stocking Pullman, Continental and Montana saddlery, and I know they've dealt with a few needs for short fenders.
- Cattleman, Westwood and Garland saddles
- March Horse N Tack
- Another tack shop
There's also Hooves Equestrian, Westways Saddlery the Western Saddler, so lots of people to look up to resolve your fender size issue.