I might work this one out as I type. I appreciate that the DVLA will be undermanned due to Covid. their phone lines and email aren't manned and trying them results in pointless effort. It relates to Larisa swapping from the old trusty Jeep Gr Cherokee to her prettier Civic. 12 June the Civic is bought, at the dealers the V5 new owner details are updated electronically, and taxed. A V5 is received with Larisa as reg'd keeper, with original civic registration. All good. 15 June She transferred the Jeep private plate to retention, so the Jeep then goes on to its original 03 plate. A retention document is received confirming this. All good. 18 June the private plate is assigned to the Civic, electronically. As confirmation the updated V5 is received showing the Civic with private plate. All good. 24 June the Jeep is sold. A sale receipt is created we both sign. The only V5 for the Jeep is the V5 showing the Jeep with private plate so that is used to demonstrate the change of keeper, we both send to DVLA. It can't be done electronically as the reference number is no longer applicable, as the updated V5 with new ref number and showing original reg number hasn't been received, and never has been since. So the confusion. Both us and seller are monitoring the Gov't site for when the Jeep shows as untaxed, as tax can no longer be transferred with a vehicle, it still hasn't happened. Today the buyer messaged to say he has received 'a' V5. It turns out that V5 shows change of keeper on 24 June, for the Civic, with private plate. While the Jeep shows as taxed on the original plate, so DVLA still see Larisa as owner, the Civic, on private plate, now shows as untaxed. What has never been created is a V5 transfer of the Civic on 24 June. That was the Jeep. So they have the Jeep transfer but have applied it to the Civic.