I thought the school crisis was caused by high birth rate and less people moving out of London?
I'm also sick of people using league tables or ofsted to say what is or isn't a good school.
Of course schools that have a more able intake get better results in the league tables than schools that have a less able intake.
But that tells you nothing about which is the 'better' school.
In fact I'm at a loss as to how you can ever describe a school is good or bad. Because there are so many aspects to it. A small school can't offer what a large school can - and vice a versa. Doesn't make one good and one bad. Does make them very different schools.
Equally schools may be good or bad at sport / music / art / drama / Sen. Which you may care about or not.
Most schools have good and bad teachers. And generally progress is determined by a teacher not a school. Typically over primary you'll have 7 teachers. Some who will be good and some who won't.
It is not possible for a school to be brilliant. All schools have strengths and weaknesses. It may be possible to find a school that suits your DC very well. Which is great. But doesn't mean it suits all pupils.