"other than to suggest that not all mixed schools are rife with sexual harassment (I doubt any are free of it either, sadly)"
Unfortunately we live in a part of inner London where gang culture is endemic, and the least popular schools (which is probably where she will be heading) have a significant problem with harassment of girls as well as violent behaviour outside school.
"because you never had the chance to let out your (justifiable) anger at the parents of the girls who actually did this to your daughter?"
How do you know that anger at the parents of the disruptive children Married refers to is 'justifiable'? She probably has no idea at all of what the parents of these girls felt about what was going on at school, because I doubt she ever met them or had a conversation with them. I suspect they were like most parents, that they were desperate for their children to achieve, and struggling to know how to address bad behaviour that takes place outside the home, (or inside for that matter).
Some very helpful ideas here by the way - I will re-read them before my meeting with the HOY tonight so I know what questions to ask.
She has been referred to what the school call a 'step by step' programme within school, and offered additional support with behaviour, but she seems to have an agenda of her own which none of us can understand.
The thing which is puzzling everyone and making her behaviour especially hard to know how to address is that she is not difficult across the board. She is popular with other children, gets on with almost everyone at school, has good relationships with some of her teachers and is often described as 'well liked'. She has no identifiable mental health problems or diagnosed learning difficulties, there is no history or presence of bullying, she has all our support. She is not depressed, as far as we are aware (and she has been seen by a consultant psychiatrist. The school are at a loss of how to deal with her.