My wifes 2009 ForTwo non MHD Turbo Highstyle failed the MOT yesterday.

It failed on a number of issues which the test centre said were probably because she does not take it out often enough.
In the last 12 months she has driven 1300 miles and the failures were

- severely reduced offside front headlight strength
- rear brake binding
- exhaust emissions lambda outside limits
- exhaust emissions carbon monoxide excessive
- rear tyres excessively cracked

The tyres I will replace and the rear brake I will strip and clean (which is what they suggested it probably needs)

However, they suggested
- that the exhaust emissions probably indicated that the cat needed a clean and that I put some cat cleaner in the fuel and run for a few miles to clean it,
-I try a new bulb in the headlight to see if that was the problem and if it didn't then the unit would need replacing.

So my questions are
- is it likely that a cleaner will cure the emission problem, and which should we use, or is it more likely to need a new cat.
- I tried a new bulb with no change, so is there any way to 'repair' the reflection from the headlight unit, or will it need replacing.

Hopefully some of you have had similar issues and can advise on how you dealt with them.

Thanks.