You are most likely correct in your context (UK&NZ?). In Australia, having gone through the process in a lengthy and downright painful way, I can say my personal experience says otherwise (despite polite, and considered correspondence on my part), I found VW Group Australia to be highly offensive and intimidating.
In terms of VGA taking on responsibility, I have it in writing from VW that outside the warranty period, it's ALL my responsibility, that includes the standard of technical support their authorised dealers provide. That's right, when the warranty runs out, it's all my risk whether they can correctly diagnose and fix a VW or not (despite VW being the designer manufacturer and technical standards controller), and if they get it wrong, I pay, they can continue to get it wrong indefinitely. In my case, a simple sensor issue was misdiagnosed multiple times, and incorrectly repaired (which I paid for) multiple times, the whole process stretching into a year. By the time it was fixed, more damage has been done to the car (which is the reason why I would urge Timm to attend to problems asap.
During this year long process, I'm told by the dealer they have followed ALL VW protocols, including consulting with VW, and after all is said and done, what does VW say? MY problem.
Statutory protection? In Australia, there is no lemon law, there is very limited protection and which has only been beefed up recently (1st January 2011). If you're lucky enough to have statutory protection coverage, it is still mostly up to the manufacturer how they remedy the problem.
If the dealer plays hardball, to get anywhere with the factory warranty, one has to go to court. Which is why IMHO, Timm should be firm and communicate that he expects the problem is fixed prompto, for a couple of reasons:
1. minimise further damage; &
2. lay down the paper trail.
I must admit, prior to my dealings with VGA, I had a fair bit of trust in the dealer and VGA (my mistake), and I also admit, the situation in your country may also be different. My post is purely from personal experience.