Further to my earlier post I have discovered I need a Lambda fooler so the ECU thinks that the cat is doing a good job. The race cat I have is doing the job properly for the mot but not for the ECU hence EML on all the time.
I have been told you just plug it in to the lambda sensor@ one end and the car@ the other.
Does anyone know where to get such a thing? (it's for a 2.2)