Just spoken to the Guy at Exeter DVLA office who deals with kitcar inspections.
They are accepting the chassis number I made up. Aparently it's all in the first three letters. If the combination is already assigned to a car company then you can't have it. World database apparently!! Sounds impressive.
Anyway, well happy as I had already stamped the number onto the chassis.
Got his direct phone number as well so no need to go through Swansea anymore.
Cheers
Mark