HRH it’s a while ago but this guy got good report from a local off-roader we met on Luing. it’s Hazelbank Motors, Mill Lane, Oban, PA34 4HA hope it’s of some use my friend.
If you're anywhere near Falkirk, Jim Allan Motorcycles has always been very good price wise(usually within a few pounds of internet prices) and usually gets the tyres in in a day or two.
I prefer to take them in the loose wheels but for a little extra he'll do a drive in / out.
Highly recommend Bellsburn motorcycles in Bo'ness. He fits for very cheap ride in ride out. I ordered tyres online cheaper than anyone could provide them and got them delivered there. Believe he charged 20 quid for fitting.