how come only the back windows and back windscreen are tinted? why not the front windoes aswell?

 

Can't speek for UK, in Germany it's illegal on the front side's. Just rear side's and rear.
Probably the same in the UK.

 

Yes same in UK. Safety issue.
Got a friend who just bought a Lexus RX300. Front side windows have this coating as standard which repel water (into bubbles) and slides off. Why don't BMW have this as standard too? Nice gimick I think.

 

In California, the law says no tint on the front windows. Many people tint the windows and hope they don't get a "fix-it" ticket. Same for the front license plate.

These are low-pri for the popo.

I also kept my new car sticker on the lower front right passenger side of the windshield. Even though it can be removed after you receive a license plate, I left it on so I won't (hopefully) get a ticket to put on my front plate.