I have it. I managed to negotiate down to £300 as part of the deal at the VW garage. My view is £300 is a small outlay compared to the purchase price. A standard 3dr GTD is £25565 of which, 20% is VAT coming to £4261. If you were unlucky enough to have the car written off within a few hours of collecting it. The GAP insurance would cover the difference between your car considered now as 2nd hand with 0% VAT and your initial outlay of £25565 including the VAT.
Conversely you may never need to claim on it so the money would be lost.