IOTL some Boeing 727s were refitted with Rolls Royce Tays. There was also a plan to refit BAC-111s with Tays. If more VC10s had been built then the Tay might be an alternative to refitting them with RB211s.
That would be a good idea. It would look better with 4 Tays instead of the two huge RB211's
In fact when looking at the concept, i cant understand why the RAF DIDN'T re-engine it's aircraft with Tays
It's more efficient than the Conways they used up until 2013.