Didn't Charles have terrible experiences at Gordonstoun...bullying and harassment and such?
He did but his father, brothers, nephew and niece all report that it was wonderful and loved it (although I notice that none of the boys sent their children there, although Anne did).
I imagine Anne sent her kids there because she wanted to go and was unable when she was a kid (example of a parent living through their children maybe?). Fortunately Zara and Peter loved it, which given their upbringing and mother's temperament I'm not surprised! Maybe had Anne been allowed to go and experienced it she would have deterred from sending her own kids there.
Though given Anne's similarity to her father, she would have most probably thrived at Gordonstoun in a way her siblings didn't.