I'd be interested to hear the story, though, as you say, it's too late to do anything about it now. I suspect that someone got the wrong end of the stick, and/or gave you some incorrect information, and that your rejection could have been appealed if it was justified on the grounds of where you went to school. If you think about it, there are tens of thousands of HMG employees worldwide who have to send their kids to a whole variety of schools, many of them local nationality schools, and the idea that their kids could not be employed by HMG because of a situation forced on them by HMG is laughable! Anyway, as you say, it's history so I shall vacate that particular soap-box! Suffice to say it didn't affect me or any of my mates, thank goodness. Good luck on your second try at a flying career!
Scroggs