I don't mind it, it may infringe on a few incorrectly (which would later get corrected I assume), but it should catch more criminals and prevent more crimes, overall I think it's well worth it. The standard of it probably goes up exponentially also.
I don't mind in the slightest being watched everywhere I go, they can log it and keep a 10-year report if they like, and I wouldn't be surprised if they already did.
People won't be locked up in advance for crimes they've not committed, the law would never allow this, and for it to be passed as a law the public and MP's would have to propose, vote and allow it, it's not going to happen.
Generally, people who commit crimes are more likely to commit the same crimes or other crimes again, anything to help that is a good thing I think, especially when we have fewer police.
Any private premises has a right to deny anyone they wish, and if they want to deny known offenders to them, then they should be allowed to do this and be able to use all the tools available.
I doubt private places will be given direct access to national crime databases, the data protection laws and basic rights wouldn't allow that I expect, but if companies want to store faces and ban faces from entering their premises then fair enough I think.
I think football clubs have nationwide databases, for hooligans etc, but by entering the premises you're effectively allowing yourself to be entered onto the databases.
As for protests, these are fine when they're not getting in people's way, they can stand and shout at the sides. But the protestors don't do themselves any favours when they prevent people from going about their daily lives, hampering emergency services etc, or causing damage to property which is not theirs.