when selling a car which has a private plate that I want to keep, what is the procedure? Do I have to remove plate before selling a get new V5c or can I sell car & transfer plate to either another car or to retention at point of sale?

http://www.theplatemarket.com/dvla_number_plate_forms.php

This is a good guide and you can sell your car with the plate but let the new owner know that you are keeping the plate and when the paper work is done the plates can be changed

You need to put the plate on retention, £120, and wait for the log book (V5) to arrive back before handing the car over. When the V5 comes back to you it will have the new reg number on it and also the new tax disc and MOT ticket also with the new reg number on them. When you receive all this you can then change the plates on the car.

 

Once the private plate is on retention you must put it on to another car within 12months or keep paying £25 a year until you do decide to put it on another car.