Tony thanks for that ill have a good look inside the cat.

As i said if it was not for the lambda sensor code
I would be changing the cat based on the co reading
wich is exactly as a normal car with no cat.And
sensor 1 fuel trim good in closed loop and all other gas bench values a pass and lambda 1 confirmed on gas bench.
Its the slow switching lambda and the code thats
got me nervous of cat replacement. would be an expensive mistake if new cat made no differance
.
and yes all exhaust bolts are shot and will need
cutting off. ill look in the post cat sensor hole
back up at the manafold first