I have no idea where the clear plastic bags in the UK came from. I assume, based on the short-notice regulations, that the airport was supplying some.

There is no carry-on ban any more.

The carry-on restrictions in the UK are limiting, but I think reasonable. (Certainly more reasonable than a "no carry-on" rule.) I have no idea how the restrictions compare with the rules pre-last week.

Yes, books are still banned. But this has nothing to do with airports and travelling. Books are most certainly allowed onboard aircraft.