As long as the registration mark is not a non-transferable registration mark (this will be noted in the Special Notes section of the V5C Registration Certificate), then it is possible to remove it from the vehicle in order to sell it. A non-transferable registration mark cannot be removed from the vehicle.
We spoke to VRM in Swansea to get some advice on how to go about this. First of all, the vehicle will need to have valid road tax (even if the vehicle is tax exempt and the tax rate is free) or have had a SORN in place continuously for the past five years. It will also need a valid MOT certificate (even if the vehicle is MOT exempt). In some cases, the DVLA will also require the vehicle to undergo an inspection.
VRM's Gemma Smith, said, 'Once the registration has been removed from the vehicle, the DVLA will issue the vehicle with another age-related registration mark - in this case, the replacement will be a dateless style registration mark (these were issued to vehicles between 1903 and 1963). The replacement will be non-transferable.'