Update
Well, the dealer rang today saying they'd fixed "most of my issues". As an example, they'd ordered a new seat base to cure the creaking from there. In other words, this "adjustment isn't covered" is nonsense. I don't believe for a minute I need a new seat base to cure a creak but if a dealer says this to VW they get paid. So it boils down to the dealer making an effort and so far Donny at least seem to be trying hard to sort things.
Interestingly, the alarm fault that came up on Darren's VAGCOM doesn't come up on the dealer's computer so they've sent a technical inquiry to VW UK at Milton Keynes to try and sort that one out. We'll see what comes from that. They're happy for me to keep the Jetta until everything's sorted so fair play to the dealer so far.
It may be ready tomorrow but that depends on the technical inquiry. I will keep you informed though.