It's just another petty revenue gathering exercise...our ANPR system is modelled on the UK version and has no problem reading the variations which crop up. The main thing is the actual dimensions of the plate and the size of the lettering/numerals...if they fit into the grid and are the right colour, they are OK. As a matter of fact, many of our police cars are fitted with plates which feature displays which are different from my 'standard UK' one.