VW can't win, they delivery months later and get slated, they deliver months early and get slated

Maybe the dealer has had a customer cancel and you've taken their build slot or maybe folk are fed up being told its a 6 month wait so have went elsewhere and the rush as quelled a bit.
That's a big ask, asking the dealer to keep the car from December until March. I suppose you could tell them you had worked out your finances on the car not coming till March like they said so it is now inconvenient and can they help you out.
What is it on the Nav pro you prefer? Just the onboard storage? You could always attach a hard drive via the USB if its capacity your concerned about!
Did VW say anything about the Rear View Camera? I emailed them asking when it would be available to order again and they told me about the shortage and that's why its been removed so those that ordered it would be guaranteed to get it.
She reckoned it would be back soon but wouldn't commit to when.