Are you sure that was full-time? I thought NMW was around £22k now for a 37 hour week. Disgustingly low for a management job though.
A friend works in a care home in Suffolk. She gets a few pence an hour more than most, because she was a senior healthcare assistant and can do some medical stuff that other staff can't, and she's still only on £12.20 an hour. She works a zero hours contract by choice, as it means she can turn down any shifts she doesn't want to do and they can't make her work over never works Christmas.
The place where she works really struggles to get staff, as do all the others in the area. To keep the staffing up to the minimum required, they use a lot of agency staff from South Asia, and the agency charges the home £16+ an hour. If they were prepared to pay £16 an hour to everyone, they might not need the agency staff.
It's a really challenging job, the residents all have dementia and frequently become violent, and most of them are doubly incontinent. A lot of new staff can't hack it and leave after a few shifts, which isn't surprising when they can earn more in Macdonalds or Aldi without doing night shifts or being bitten and punched fairly regularly.
I wouldn't do it for £50 an hour, frankly.