What a truly lovely lady DVLA has working for them !
"I have been in touch with the case holder, it appears the number plate was transferred on this vehicle, some time ago, the replacement registration will be SSK 476, you would have to await the V5C to obtain replacement plates and this is now going through that process, if you have not had a V5C by 20/12/19 please feel free to contact me again."
WOW Hopefully if the document does come before the 20th it would of only taken 3 months! (and I did tell them the number had been transferred) from the 21st Sept when I applied.
Better not hold my breath just yet but does look promising.