Checked the cam timing, was amazed to see the tensioner for the belt between the 2 cams had lost its plastic outer, so i suggested i replace both the belts and all runners before i go any further, which i did. But that wasnt the main problem. The bits, of which there was 7 of them, had found their way below the crankshaft sprocket and wedged themselves between the back of the belt and the belt cover, bits of these plastic pieces were mashed into the cam belt teeth itself and the crankshaft had jumped 2 teeth, the cams were still timed together ok though. Replaced everything and set up correctly and emissions were instantly borderline, a good hard thrash got the cat clean and hot and the emissions came right down. How the hell did this not break, and how did it run so well with the crank 2 teeth out? Its all good fun.

Thanks all.