how would i go about breeding my male working cocker spaniel who's grand -father is a field trial champion

You will have to find someone with a working bitch who wishes to breed and thinks your boy fits the bill, both in working ability and the lines he is from. If you work your boy then let it be known that you are willing for him to be used at stud.

Can you not get advice from the shoot you work your dog on?  What are the attributes your dog has over and above others?  It's nothing too unusual to get FTCh in the pedigree, is this on the sire or dam side?

If your dog is any good as a working specimen, and he has had eye checks, then people will soon be beating a pathway to your door.

Jacky