Sorry, @ KTM-AL, I only just saw your note...
I was advised by 'phone (DVLA) to send my documentation along with a covering letter to detail my request, to the main DVLA address, as per the V5C. I was hesitant to not be able to identify any specific department/section - and with good reason as now, about 4 weeks into this, I am still waiting to receive the revised/amended V5C !
I might call them tomorrow, 24th March and ask, using my licence plate as the reference.....
I promise to update via this thread on the eventual outcome (or intervening issues!).