Have you tried MCS in Renfrew, admitted they are no longer a Yamaha dealer, Triumph and Kawasaki now, but their mechanics, sorry, technicians :lol are Yamaha trained.
I know they, MCS, have recently sold their service end to someone, can't remember his name, bit it's still the same people in the workshop.
I've bought a couple of bikes from them before and never had a problem with the sales, but more importantly the service or loose stuff or marks on the bikes etc, reasonable rates as far as I can remember.
If I had the money though, I'd take my bike to Ducatti Glasgow on Great Western Road.
I know the sales guys, and also know the mechanics very well, they serviced my BMW'S at motarad Kirkintilloch when they worked there. Wouldn't hesitate to give Craig and Michael my bike and know that they would return it in better nick than I gave it, two of the best guys in the business in my opinion