My thoughts on the hospital thing and I am 4 pages behind so you all may have moved on.
But if Mark comes into A&E with a cut on his hand, tests positive on admission and has to spend a night to see a plastic surgeon the next day (but is later discharged after 18 hours). Mark would have to spend the night on a Hot or Red ward as he has covid, these wards are wards that were used for other things but now are used solely for covid positive patients.
So it doesn't really matter if a covid positive patient is there for 2 days or 2 months, they are still using a bed on a ward that could and was being used for something else pre pandemic.
The hospital admissions data is updated regularly so Mark wouldn't still show on the hospital stats when he has left the hospital.
Also in our local hospital staff that work on the hot wards must stay on the hot wards. That goes for everyone from drs, nurses, porters and cleaners. You can't switch between them, to try and protect patients and stop in hospital spread. The more people being admitted with COVID-19, wether they have no symptoms or have loads, is using staff from other places. So as far as I can see the hospital admissions data is very important.