BoneyBack
It seems, from the tone of your posts, that you do not approve of private schools. Or have some issues with them at the very least, because you seem to assume that as it is a private school that there is likely to be problems along the way. That may be borne of experience or an ideological stand point, I don't know.
I hope that the school that you choose does your children proud and that you are not to blinded to see if it goes wrong
I hope that I would recognise the fact my child was struggling in some way with school and that I would do so long before it "all went wrong"- although like most parents I am not perfect and do get it wrong sometimes. However, I don't see that as only a problem for parents who chose a private education for their children. I am somewhat bemused as to the reason behind your assumption that it is more likely that we would be neglectful of our DC's well-being/ likely to be wilfully ignorant or "blind" to a problem our DC were having because we have chosen the private route. I am genuinely surprised that you'd make such as assumption and (though I'm not sure why) a little saddened.
As I said, I have no doubt that many private schools are not the right place for SEND children. Very many state schools aren't so wonderful for SEND children either though (and some are downright awful), so it is not as though state schools are universally excellent in that respect either.
I am also more than aware that not all private schools are better than state schools. Some are positively mediocre whilst some state schools are excellent. However, many private schools are also excellent and provide a wonderful education for their pupils.
But you are right in that I have made a choice. A choice that I believe to be right choice for my DC, who appear to be thriving thus far and have been given some amazing opportunities. It is, of course, possible (likely even) that this school would not be the right school for every single child. However, I know that our other options in terms of state schools would have been inferior. If we had excellent state schools local to us, we may have made a different choice.