IIRC the VC-10 engines and horizontal stab. were returned to the UK.
The stab became a spare when a mod. program required removal for the work to be carried out.
I saw the engines at Heathrow during a visit to BOAC in 1971. They were all covered in sand. It was when the first 3 B747s had been delivered but were not flying due to union action.
I suspect the rest of the VC-10, the DC-8 and B707 were scrapped on site.