How can I verify the CO2 rating of my Volkswagen Polo?

I recently privately purchased a 2006 Volkswagen Polo 1.4 SE 80bhp. How can I independently check the CO2 rating? The V5 states 156 grams per kilometre, whereas the original supplying dealer to the first owner quoted me 150. It's not a big deal but does notch the car up a bracket in the VED stakes. Also I think I believe local advice that the original cambelt should be changed now, having passed the four year point.
The taxable CO2 is whatever is printed on the V5C registration document and cannot be changed, but you can check the theoretical CO2 at:

Yes, the timing belt and tensioner need to be changed.
Answered by Honest John on

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