Hey mate, am in Scotland and I normally use JM Imports in Newcastle which is a bit of a drive but the service is really good and your roughly 750-850 for a 72 month service.
If you want to stay in Scotland then I would recommend Garage-R I have never used them but I know Matt and he will look after your car and he knows if stuff.
Apart from that there is not much other places in Scotland am affraid. I have used HQ garage in the past for a 48 month service and they are located in Dalgety Bay but I would prefer to use a independant specialist if I were you.
Hope this helps