Ring them up before you travel.
I know someone went for their appointment only to find the Doc had gone on holiday.
PS, on refelection I used to go to the Eye Specialists at Kelvin House. The routine was simple. Arrive, process, examined by an opthamlist, notes written up, reviewed by the Doc and regraded. I do not even remember him looking at my eyes.
Ditto hearing. Technician did all the tests, proved what we already knew, which was why I was there. Called in to Doc who said yes, I was deaf. He might have looked in my ears but he was really unnecessary.
Ditto heart. Med Tech at a secret air base got a duff reading. Arrived at hospital, processed in. Senior Med Tech did further check and said don't think you will be staying. He could not tell me there was no problem (he did though) but I could not leave until the Doc agreed.
In essence it was techincians every time that did the work and knew what the result was.