just thinking out loud, so bear with me.......
if the new car has a 50% rebate, grand.
But, VRT on a used car is calculated based on the OMSP of a similar one, here. That OMSP already reflects the reduced VRT, so no, you wouldn't get any rebate on the VRT on a used one. To support this look at the following example, which I looked up VRT on:
Example:
Used 05 Prius, 10k miles, here: Eur 25000
Import of UK car = Car at 21600 (app 14k Stg) + VRT of 2947 = Eur 24573
which, amazingly, is uncannily 'equal' : isn't that a shock ?
Subtract ferry and time off work (maybe), and forgetting you could probably get a discount here anyway and.............there's no saving.
Amazing, really. Not. !