I do think some of the comments about Ms Birbalsinghe are somewhat harsh.
I never saw her original (anonymous) blog but my understanding was that the children referred to were suitably anonymised and the examples in her book were not necessarily literal accounts but composites. I'd accept though that it was perhaps sailing close to the wind to show pictures of some of her pupils at the Tory Party conference, though she did claim that she had only done so with permission.
There have been a number of anonymous blogs by teachers, policemen, social workers etc etc giving an account of what life in life at the "coal face". Such people put themselves at some risk if they are outed but I think they provide a useful corrective to what we read in the mainstream media.
She expressed the view that our secondary education system is broken and went into some detail about why. As a result of this she was forced out of her job, dropped like a ton of hot bricks by her union (who are supposed to fight their members' case and would have surely taken her up as a cause celebre had she made a rabble rousing left wing speech at a a Labour or NUT Conference) and informed by recruitment agencies that no state school would ever touch her again with a bargepole.
Rather than just roll over and accept the destruction of her career she decided to step up to the plate and accept the challenge of setting up her own school.
She may have an ego and flair for publicity, but that isn't exactly unusual in a head teacher, and can be turned to advantage. I wish her luck.
I think quite a bit of the hostility towards her is from vested interests in the educational establishment. As John Prescott so memorably put it, "If you let people set up schools and they turn out to be good schools the problem is that everyone will want to go to them." Quelle horreur!
Incidentally I have no connection with her or the people setting up her school, nor do I have any personal interest since my own children are getting to the end of their secondary school careers.
I remember the stress of secondary admission and am glad I won't have to go through it again - also sympathise with those who are going through it right now.