I will have the car serviced by a different dealer to keep the warranty good, and the software updates as they emerge. Ordinary non-warranty work that doesn't involve the HV electrical system will be done by my local garage, though. If the damaged undertrays/wheel arch liner do need replacing in the future he can get the parts in.
When I got my previous car, a Golf, I checked with him that he would be able to service it from the get-go, because there isn't a convenient VW garage to here. (In contrast I can walk home from the local garage, or catch a bus to work at the bus stop right outside the garage entrance - or I could before I retired. Or sometimes I was picked up by a colleague who drove past that way.) The car was three months inside the end of its warranty when its engine blew up. We had a bit of a to-and-fro because VW wanted to repudiate the warranty because it hadn't been dealer serviced. However Andrew, the garage owner, was able to prove that he had done everything right and used all approved VW parts and they had to give me a new engine for free. Out of spite they refused to give me a courtesy car, but I managed to hire a cruddy box for a couple of weeks, so all in all I was quids in.
Unfortunately Andrew isn't yet equipped to deal with HV battery issues, and even if he were there's the matter of software updates, which weren't really an issue for a 2009 Golf. I think dealers have us over a barrel these days while the warranty is in force, but that doesn't mean we have to let them fleece us for ordinary non-warranty issues like brake maintenance and undertray damage.