Thanks for you reply. Can the dealer register the car before I’ve signed and given my pin?
Yes they can. As I said, my new car has been given its registration mark already and I don’t pick it up until next Thursday. If they have already registered the car, I am not sure if they can de-register it so you will either have to accept the 74 plate (which I would not do) or cancel the order and possibly go elsewhere. Please can I ask what car you have ordered and are you prepared to accept the 74 plate or cancel the car?
The dealership that registered the vehicle can apply to de-register it upto 7 days from the date of original registration:
https://www.gov.uk/government/publications/v996-application-for-de-registration