tried to get my racing puma mot'd today and the co2 was 8.5 instead of 0.35, or something.

How roasted does the cat have to be!! or is there something very wrong there

 

even with the cat removed it shouldn't be that high, sounds like another prob in there, did you see what the lambda reading was or the hc's?, as these often give away clue's as to another prob

 

its broken get it fixed

 

As said even without the cat it should never be that high, have cars in without the cat fitted and still pass

 

check you HC, thats ALOT more important to tell you about the engine, ill bet its over 300, the limit is 200 BUT anything after 60 means a miss fire ect

cats are only there to assist the excess rather than do all the work