I have been attending OP appointments for years. It used to be the case that you made the follow up appointment on the way out and it always happened. Then around twenty+ years ago it became a case of "we will post it to you". This usually happens but sometimes not and you have to chase. Also quite frequently another letter arrived changing it to a later date. Sometimes this can occur a multiplicity of times.
I received an appointment I cannot make as I cannot be in two places at one time! Anyway I rang up to change it. An alternative acceptable date/time was found a few weeks later. Then to my surprise I was asked exactly why I could not make it? As they always say "unforeseen circumstances" this felt like an intrusion. Hopefully they are not going to start recording this just because they can!
It reminds me of some years ago.i arrived late for an appointment (train stuck between signals - I had rung up to let them know) and the receptionist recorded I was late. When I asked if the doctor was waiting she said "Oh no, he's running 45 minutes late". I did not get a smile when I suggested she record this as I was only ten minutes late!