Well there is a happy ending to this one after all the hassle
Isuzu main dealers discovered a multitude of rebuild mistakes
Timing incorrect cams incorrectly installed kinks in the fuel line etc
After 1 full week and a huge bill later (payed by the garage who cocked it up) the car has been brought back to life would have had it this week if lambda sensor had not have caused a engine management light to appear on the dash due to a adjustable fuel regulator that they had fitted because they destroyed the original.
So hopefully now i can enjoy the car at long last.