I visited the hospital to attend an appointment last year which was the first appointment I was aware of. When it was my turn to see the nurse she was a bit funny with me about missing my 2 previous appointments. It was the first I'd heard. Do they make you an appointment but fail to notify you.
Another one, a year or two ago, I received an NHS letter one day and when I opened it it was for an appointment for 2 days before.