So, legally, you are allowed to tint the rear screen, side REAR windows, and.......nothing else.
We had a Vauxhall Zafira (when we had heaps of kids to tow around) which I had a full body kit fitted & some nice alloys with low profiles, so the next obvious mod was tinting the glass.
I went to a local window tinter, and explained that I wanted to go as dark as I LEGALLY could. I was pleased with the results, even though I would have liked it a little darker.
About a month later, my wife was chased down the road by one of those pretend police cars that you usually see patrolling the motorways (can’t remember what they are called) and told to remove the tints on the drivers and passengers door windows, there and then, or she would be issued with a fine. She called me & I told her to come home with whatever paperwork they wanted to give her, and leave the tints as they were.
I called the manager of the unit for the pretend cops & arranged to meet him in a car park where he used a meter on the windows & confirmed they needed removing as they were illegal. I argued that the reason for the law was to ensure it was safe to see through the glass, and he agreed. I then stood to one side of the car with all the doors shut, and looked through the car to the next car in the car park where a guy was reading a newspaper, and pointed out that I could still read the headlines through 2 windows on my car & his side window, so where was the logic that my car was illegal?
He agreed with me, and said that as the meter said that the light passing through the tinted glass was below a set percentage (can’t remember what) regardless of what you could actually see through the glass, the tints had to come off.
I had to go back to the tint company & get them removed, and then go to an mot center and get the glass re- tested & send the result off to prove it had been done.
You do see cars with almost black side windows, so I can only assume, they simply haven’t been caught yet.
All in all, simply not worth having the front side glass done, but you can go as dark as you want with the back of the car.