Paul, please put your location in your signature line or under your avatar--that will help.
Various methods... banding them--I have no experience w/that, but some here do. Believe it's most successful w/in the first year, and the head won't be smooth, but won't grow.
If it's a large scur, and not a real horn, per se, you can cut it (wire saw, or even sterilized nippers, depending on its size), and cauterize bleeding tissue w/a disbudding iron. It may continue to grow, however, and would have to be repeated. Wouldn't cut too much off at once, just b/c of the bleeding issue.
Surgical removal-- TX A&M does a procedure where they close the hole w/skin. Other vets would cut a hole through the skull, removing horn & skull tissue, and not close it over w/skin. (unless maybe you could get them to consult w/A&M and try a new-to-them procedure?) This leaves a hole right down into the sinus cavity. I had it done on both of my bucks, and it's pretty ugly until it heals. Like any open wound, there is danger of infection, and you don't want to do it during fly season. Maggots-yuk.
I'm a big wuss about disbudding even, and an older animal is just no fun at all to inflict pain upon, so I like vet methods, because 1. they involve sedation, and 2. I don't have to be the bad guy!