I had a referral to the hospital for a specialist appointment, after being on a waiting list for some considerable time. The appointment was during the day, and so I took a day off work for it.

My contract states the company will give a reduced rate of pay for taking sick days.

However they said that a visit to an appointment is not a sick day.

It wasn't possible to schedule this visit out of working hours, or even at all due to the very long waiting list.

Are they correct, does attending this appointment not class as a sick day?

I have a doctor's note proving that I attended the hospital.