+8 2024: How to know whether it is worth it

[Laurettap2]

Hi there
My DS is in Y2 at a local prep and, while until now I've never considered moving him, I am starting to realise that he might enjoy a more challenging environment (besides the fact that I am not happy now with what the school has done with my eldest who is in Y6).
We are too late for 7+ and I am considering 8+ next year.
We are based in SW London so it would be for the usual schools (St Paul, Kings). How do I know if it is worth trying? How much work should I put into it?
My DS is very good at Maths and he actually enjoys it very much and average at English.
Any thought/advice super appreciated.

Some of the schools have a sample papers - see if he can at least make a decent stab. Then I would get a tutor who has the knowledge of the asks of each school so ds can practise.

Thank you!