Try reading Roly Beamont's book about aircraft he has test flown; he has some very specific things to say (sorry can't remember the title of the book)
All the early teething troubles were being fixed or had a fix in the works apparently; he reckons it was an entirely political decision.
Don't forget Labour cancelled a lot of other aviation projects at this time eg the Hs681 four engined high winged military transport, which the later HS/BAe 146, although smaller, looked very similar to(but the yanks wanted us to buy Hercules). I seem to recall a derivative of the '681 would have had four Pegasus engines (as fitted to the Harrier, then being test flown as the Hawker P1127) thus giving it very short takeoff performance.