Yeah - I've escalated it. I'm not very happy with the situation.
First the roadside assistance guy said my closest van centre wasn't accepting new jobs atm, so he suggested the next closest (it seems without checking availability). VW did originally say I can move it (to a van centre even further from me) but AA want me to pay for the privilege. VW didn't make it clear there would me a further charge - they just said to ring Roadside Assist to sort it. For it not to be looked at for so long, and with no courtesy vehicles available is a bit of a joke.
Let's see what they come back with... Will post updates as I have them.