YABU. I've been caught up in roadworks and an accident. On those occasions I've pulled into a safe place to phone my GP's receptionist and explain situation. Chances are high that other patients coming from your area will also be late, therefore concurring your reason for being late. It'll also let them know to expect other patients to be late from your area too and give them and yourself some leniency. However, I always add in extra time for my journey too, just in case.
I've found that setting my watch ten minutes ahead helps in an odd sort of way. I always aim for the time on my watch knowing I've got ten minutes allowance!
Whenever I phone in with a reason as to why I'm held up due to no fault of my own, the receptionists always say to me that my doctor will see me at the end of surgery. After all, if you're really ill, you'll wait. If you go to your pharmacist to get medication for your LO it seems that an appointment wasn't actually really required.
I'm also lucky that I can usually get an appointment with any doctor on that day. Probably because I have several serious conditions which can very quickly escalate into something worse landing me in hospital. I only tend to make appointments when I'm dropping dead, almost literally, as I hate going and possibly wasting their time.
I think they have some sort of system that alerts them to the more vulnerable patients. By seeing me that day, it often prevents me from landing up in hospital for a week or so, using even more of the NHS's valuable resources.
As my GP says; "you never come in with anything boring like a cough or something. It's always something interesting and serious. You're one of my very few patients that only make an appointment when really needed!"
Somehow, that just makes me feel even more guilty for being there! 🙄😴