As far as the loss of entitlement is concerned, I do the following. Every year, I have to have a PCV entitlement renewed because of my age (groan). I have to send in my old licence, so, for fear of losing my motorcycle entitlement, I send a stamped addressed envelope & request return of my old licence. This then comes back with a hole punched in it to render it invalid, but at least you have the proof that you want, if further issues develop. I heard of a motorcycle policeman who had the same trouble & the DVLA were adamant that he had never passed a motorcycle test! Mistakes, by DVLA are numerous. Many mistakes are made when a change of ownership is made to vehicle records. In the end, if they are minor, I let them go as if returned for correction, they often come back with more mistakes than ever!