Dc2s school do boxing for half a term in PE. The school did it last year with DC1 who ended up with an eye injury after their friend got a bit rough being silly. Big group of kids, all beginners and not enough control of the group and I believe it was stopped early.
Teacher is a PE teacher but not as far as I know a qualified boxing teacher.
I'm not against self defence or martial arts at all but boxing with a proper boxing coach who is insured and used to teaching beginners classes would make me happier.