Noise Limits

[lateconvert]

Pardon if this is an oft-asked question, but how can you find out if your car will pass the noise limit test, other of course, than booking a place and turning up in blissful ignorance to find that it fails on the day?
(TVR Chimaera 500, standard exhaust).

[lateconvert]

Thanks guys, very useful and reassuring input.