Confirming the above posts, I believe the last civil-registered VC10 to fly belonged to HM Sultan Qaboos of Oman (A40-AB). He kindly donated it to the museum at Brooklands (UK) in 1987, where it still resides. If the one you saw at LCA definitely wasn't in RAF markings, then it must have been the ubiquitous Il-62.
It is
rumoured that Angola Air Charter may still have a serviceable 707
