I'm not too far away from you in Bruton. I've got a 2019 T6 California and over the years I've used Mon Motors (previously Heritage) in Bristol, Breeze Poole and SMV Commercials Yeovil. The latter used to be a VW Service Centre however they stopped that side of the business about a year ago. A shame, because out of the 3 although they were a bit rough and ready (the garage handled HGV as well as LGV) their technicians really seemed to know their stuff. They will still work on VW Commercial vehicles however can't do Service plan or warranty work. So in that respect when you are off Service Plan I'd definitely recommend them.
I've used Mon Motors in Bristol a few times for servicing, most recently in April this year, and have no complaints so far. I was particularly impressed by the video walk through the technician provided when he was doing the underbody health check on the van. So at the moment they are my preferred garage for regular servicing work. I doubt I'd go back to Breeze unless Bristol couldn't book me in, Poole is a nightmare to drive into and they just don't have the space there for the volume of work they seem to take on. I had them check the tracking on the van and even just parking up in the morning was stressful, never mind checking in.
Have you thought about VW Heritage of Dorchester - they aren't too far away from you? I haven't tried them but they are an option.....