Aint the web great

a little google trawling brought this up
When you sell a vehicle with private number plates assigned to it, the new registered keeper acquires the rights to the registration number. If you wish to retain the rights to the private registration there are two options. Firstly you can transfer the number plate onto another vehicle you own or secondly you can transfer the car registration number onto a V778 Certificate of Entitlement.
Holding a car registration on certificate means that you can retain the rights to the registration without it being assigned to a vehicle. Applicants wishing to use this facility should complete DVLA form V778/1 and include the V5 logbook, MOT (if applicable) and the retention fee of £105 payable to the DVLA with the application. To transfer a number plate from car to car you must complete DVLA form V317 and include the V5 logbooks, MOT certificates (if applicable) and the fee of £80 payable to DVLA.
By selling private number plates you are effectively waiving any rights you have to those particular registration numbers. If you wish to sell your private number plates there are a number of options you can take. Firstly you can sell the vehicle with the car registration still assigned. The new registered keeper will then have full entitlement to the number plate. Alternatively if you are holding the number plate on retention you can sell the certificate to a willing buyer. You will have to have the buyers name added as a nominee if they wish to assign it to their vehicle.
To add a nominee name to retention certificate the owner must sign Section 1 and provide the nominee name. The certificate must then be sent to the DVLA with payment of £25. An updated certificate with the new nominee name will be sent out typically within two weeks.
£25 , not bad , was expecting much more than that
feel free to chip in if the above is not correct
