Sam will be fine. I think sometimes it's better not to be there when they are getting trimmed as they are not always looking for you. Are you going back to Sam's breeder to get him trimmed or are you going to a groomers?
I never thought of going back to the breeder's, but it's a 2 hour drive there and back! He is going to Wizard of Paws over in the south side of Glasgow. They let us take Sam in twice for him to get used to the staff and all the noises. They also popped him up on the grooming table and gave him a brush just to see how he coped and he seemed fine. 1st time he wasn't really sure, but 2nd time he was fine.
I am completely fine with him going, as my last dog (pomeranian) had to be groomed quite regular. The only reason he is not going to the same groomers is that it has been taken over and they crate them when they are finished. I know it's better than them all running about, but with Sam refusing to even go his at home, I didn't want to add to the stress.
JaspersMum - I think I might just have to slip some of this into his tea!!!