On 13/02/2019 at 14:04, xman said:

Most likely story its a cheap aftermarket cat with minimal precious metal content.

 

Once a cat is up to temperature, virtually all CO is converted to CO2, at idle speeds it should be a walk in the park. 0.2% is very generous indeed.

 

I agree I can't future recommend Tony Banks

So much for the Tony Banks reputation! Its obvious their Sports Cat have no catalyst at all, effectively just a though pipe. Hope you get your money back from him. You have enough evidence.