whats the score with the law & window tints now

i know the police can tell you to remove them if they block more than 25% of the light or summat and if you dont within 24hrs you get a fine

but what if you got tints done a few years ago to the legal limit then? can they still do you for it?

my RST tints are well dark, but when i had them done, they were to the legal requirement, where do i stand? cos they can get fucked if they think im gonna take it off