If you look under the bonnet there should be a metal label riveted to the panel adjacent to the bonnet lock.
It will be a 3 digit number, mine for example is 744 = Brilliant Silver.
This is mine, not sure which is yours. Look in the last page of your service book, look for the word Lack, German for something.
Note that mine has an 8 on the same line as 744.
AANDY in the first post the picture shows a sticker previously peeled off. Ther should infact be a Service 24h sticker there with some emergencey phone numbers. If your interested in a replacement sticker why not ask your dealer im sure it wont be more than a few pence.