What part of "ANPR cameras cannot pick up the small identifier on a vehicle number plate" are you having trouble understanding?
Clearly, according to you, German cameras photograph the front of offenders vehicles, how else can they photograph the driver?. I would remind you that hge only requirement for a country identifier is that it's positioned on the REAR of the vehicle, so it cannot be seen by a camera photographing the front can it?
As for the colour of offending vehicles (in the UK), ever heard of flash photography?