It seems a lot do this, and with the incentives around I will be doing it too hopefully on a Clubsport, as the drop in used Mk7 GTi prices means the cost to change has grown more than I wanted with my normal expected discount from list and cash to change level.
As far as I have seen and read, it is not stated in any Terms and Conditions that if paid in full within 14 days, the deposit contribution is re-claimed by VW. Need to check that myself in person, but never heard of anyone having to pay that back and I'm sure we would if that was the case.
All the brokers I have spoken too when saying it will be a cash purchase have told me to go for PCP for the incentive and pay off within the 14x days.
The bank loan sounds a good bet, if you can get lower APR and not have the cash in savings to pay off, think there was a thread on this before.
Dave