"2) In the UK people are not paid for blood - it's a donation."
I'm sure you people believe that poor Americans are required by their slave overseers to trade their blood for the Krispy Kreme donuts they can't do without, but that's not how it works. It was recognized that paying for blood would attract the wrong kind of donor, so we set up a system called "blood banking": middle-class people, the kind who have to pay dearly for their healthcare, donated blood in exchange for credit against future need for blood units from the medical system. If a relative needed blood or a public appeal went out for someone in need of large amounts of blood, you could assign your units.
But this started cutting into hospital profits, so we stopped doing the credits accounting. The medical system now has to keep wheedling for uncredited donations from the same middle-class people, generally by setting up blood drives through offices and organizations and trying to get people to compete with their coworkers. Absent the credits, they are now always short of blood.