I'm 42 and was asked a few times if I was a health or social care worker, three I think, the initial check in to give my appointment time, and some details, the next check in, where they found my appointment sheet and checked more details, then by the nurse who gave the vaccine.
I'm not in health or social care (eligible on medical grounds), but I assumed that, had I answered yes, I'd have been asked for some kind of ID or back it up. I assumed they are trying to prevent further incidences of links being shared, allowing people to book on before they are eligible, and get the vaccine by falsely claiming that they work in health or social care (or some other eligible criteria).