Well problem now sorted. My engine has 2 cats, one on the exhaust manifold, and the other in the pipe under the floor. Took off the pipe at the manifold and it was almost completely blocked by bits of cat internals. We removed the last of the cat so now it has nothing in the manifold cat. Took the exhaust pipe off and shook it, and a few bits of rubbish came out but nothing much. We put the pipe back on again and although it was better, it still wasn't right. I had tried to blow through the exhaust with an airline and not much came out. It was obviously party blocked so I put a new one on and all is well again. Fortunately the lambda sensor came out easily so I was able to reuse it. It now drives fine again!
Not sure what will happen for its MOT, but it seems from comments that it shouldn't be a problem.
Manual VVT, 2 1/2" lift, ORA castor corrected arms, 2" ORA body lift, 4:1 transfer box, Uprated front shafts & CVs ERM , ARBs back & front 3.9 diffs, 6 point cage, ORA winch bumper - Superwinch EP9, ORA rear bumper, ORA axle truses, Diff guards ERM , TBR tank guard, Snorkel, Kumho KL71.30.9.50 15
