There's a couple things about this story that I find baffling.

First, the claim that just washing blood stained fabric in extremely hot water removes blood stains is strange. Hot water sets blood stains, it doesn't remove them. Standard hospital laundry protocol (at hospital where I worked for 2 decades) is blood stained linens are bagged separately from regular linen, and chemically treated to remove the blood stains, then washed & dried at high temperatures to kill any lingering germs. As someone who has had severe nosebleeds for many years, I can attest to the fact that trying to wash blood stains out of clothing in hot water usually means permanent stains.

I realize the US and UK have different health and safety laws, but I would expect the UK would have some type of law requiring special handling for cleaning obvious bloodstains due to the risk of bloodborne pathogens - the OP knows the cause of the bleeding, but housekeeping and the people in the laundry room do not, and opening up a bundle of bedding with bloodstains may trigger issues there. Perhaps communicating to the hotel that there are blood stains on the sheets - without disclosing private medical information - so that the cleaning staff can be prepared with gloves to handle the bedding could minimize future issues.