It is hard for new arrivals to get their children into any school so I have great sympathy for you and your situation.

The poor quality of the English in the responses of those who praise this school says it all for me.

I suggest that you:
Check the qualifications of the administration and teachers.

Do a tour of the school.
See the balance between British and non-British children in classes.
Check whether the teachers are mostly British trained or do they come from South Africa and Sri Lanka as another 'poster' stated?
Talk to as many parents and pupils as you can.