My recollection is that Vigilant engine problems occured almost from the time they were introduced into service. Wasn't there intially a serious accident at Binbrook?
And when I did Admin. Officer on a summer course at 637 VGS at Rissy in '91, we had to supply samples from every batch of the fuel being purchased (at a local filling station) to Brize Norton to be analysed presumably for ethanol content etc.