I spent my evening yesterday reading this thread from start to finish. It is fascinating. As an earlier poster said, i went from
to
to
to
and back again.
OP, I really feel for you. You and DH appear to have made a series of decisions that have created a perfect storm and you are now faced with some very difficult decisions.
That said, I think you need to reassure yourselves that children, teenagers even, are fairly resilient beings. If you do decide to move your daughter from her school (which IMO, from the info you have provided, is the only realistic solution) she will cope. You tried to give your children a private, selective education, but you can't see it through. She may not understand that now but hopefully she will in the future.
What I have found enlightening is your opinions on what a 'good' education looks like. Obviously one person's 'good' may be another's nightmare.
I went to a dreadful state school. It was the only school in town and the vast majority of children when there regardless of background. I didn't enjoy my school experience one bit. However, I have achieved a lot (PhD from a top 5 global university) in spite of my humble educational beginnings. I always thought that I would send my own children to private schools as a result. But I'm now pretty certain I won't, and I think this thread has put the final nail in that coffin.
You are placing far too much value on the additional 'stuff' that may come with a private education. My teachers were fairly average, the school facilities a bit rubbish, certainly no singing during our rather uncivilised lunches. None of that really mattered because what had the biggest impact by far on my desire to achieve was my parents. They never pushed me. But they did provide me with steadfast encouragement and a desire to see and do more. To inquire. To explore. To aim above the norm. To set my sights almost unattainably high because if I didnt at least try Id never know. And I went off feeling feel safe in the knowledge that I could take risks and always have a home to come back to.
You and your DH clearly value education. But please understand that YOU can play a far bigger role in what your children achieve and do than their school. Sure, a selective, private school might make it easier for them, but what is life without challenge?
Good luck and please come back and update us. 