I was done in Swindon a few years back for my number plate on a 205Gti - The plate was the right size, lettering etc but was fixed to the front splitter. The coppers pulled me over and told me that the angle was wrong and that it sloped back.
My response was F**k off.....
....how did Mazda get away with putting theirs on the bonnet as standard on some of the MX5's.
They had no reply - They started to pick on my lights instead. lol