When I added the chin spoiler from Caterham I cut the mountains off the top of the license plate, bent the Colorado lettering back and pop riveted the plate to the spoiler. I think this would work with the Euro plate if you have the chin spoiler.
Several cops have looked at it and said no problem with what I have done. The ONABLAT is visible which is what concerns them. Down low on the spoiler the plate doesn't interfere with the air flow to the intercooler and radiator.
http://www.britishv8.org/Other/SkipCannon/SkipCannon-E.jpg