I haven’t used them but I did randomly come across a “Subaru specialist” garage on pelton fell industrial estate the other day so can’t comment what they are like.
Subaru at croxdale was ok, decent service but wanted to charge the earth and then mixed oil grades on a timing belt change which I wasn’t happy about when I found out so they got the boot, on top of other questionable visits to other garages I don’t really trust any of them unless I have to.
so I do all servicing and small repairs i can, but if you have a trusted garage I’d say stay with what you know because they are hard to find.