I cannot recall that the RAF purchased any civilian VC10's. I flew on the very first RAF VC10 that came from Vickers (BAC) and it was purposefully built for the RAF. The original contract for VC10's did not have any military connection but when that contract 'expired' the RAF tasked the manufacturer to a military requirement...no civilian conversion, to my knowledge, took place.
The tanker fleet of K3 and 4 were all ex civilian BA and East African Airways VC10's dragged out of storage at Abingdon. Having been a regular visitor to rob bits off them one was suprised when they flew out, spares having became an issue when the VC10 stores depot had the fire.
VC10s in storage
The best of all of them was the Gulf Air one parked at Brize, it was slowly gutted, I think there were issues with paperwork being missing so it never flew again... She was finally moved, jacked and her gear removed, then lowered onto her belly near the dog section if memory serves me correctly, they then decided it was in the wrong place and needed to move a bit, so she was jacked up, a full set of gear fitted then she was trundled over a bit before being jacked, the gear removed and dropped again....
We went to remove a few bits and I noticed she still had the engine fire bottles fitted with carts, so I removed the bottles and returned them through stores, I bet that caused some Stores bod some paperwork head aches..