I got a set of centre caps for MB mags from Compomotive in Wolverhampton, their phone numberis on their website. Ask for the 2.5" caps. They come with the Compomotive motif embossed on them and you can get a set of Caterham adhesive wheel badges from Caterham Parts that fit very neatly in the centre of the Compomotive caps. When you fit the caps to the wheels use a smidge of silicone sealant for added security.
I hope this helps.
deeps
Deep down you know it makes sense.