Re: Alexa, please explain...
On reflection, I wonder if the collecting user data regards their actual rogues gallery? The article said that there CCTV was of good enough quality to give mugshots for future use - so possibly they'd built their list of barred customers from their own CCTV. Hence they might need permission - or at least to have signage granting them permission.
It seems to me that the data commissioner has got it wrong here. The company seem to have behaved reasonably. They've built their list of barred users - which any company is allowed to use by just writing a list. They've automated it, but aren't keeping the photos of everyone else.
You're not allowed to keep out-of-date or erroneous data on your systems, so I guess you could argue they should have some kind of regular review of their blacklist (rather than it being haphazard). But the law allows them to arbitrarily refuse custom to people, as long as that isn't done for the purposes of discrimination, so why can't they do it with face recognition?