I've got the same car, same reg, engine size etc and the MOT tester revved the hell out the engine for some time to get mine to pass. He joked that it passed because it ran out of oil. Shortly after that i blew a piston ring and burnt a hole in my valve - different cylinders - still ran for a couple of thousand miles in that condition, drank the fuel though

These engines are crap, but i'd try the lambda sensor. Fits disceetly in your pocket when you are at the scap yards

If that doesn't work, try bribing your MOT tester

I find whisky works well
Pete.