You have to bear in mind that until a few years ago (4, I think, Sally-Anne can confirm), the two Challonerâ€™s schools set their own pass-mark in the 11+ and hence there was a certain cachet to attending them as opposed to Chesham High. Now that is no longer the case, the playing field is more level, but that change wonâ€™t have shown up much yet in terms of public exam results.
You could always ask to have a look round Chesham on a school day, we did this and they were very accommodating (which certain other GS were not).
I know a lot of parents with children in Years 7 and 8 and have never heard one of them say a bad word about the school. The only complaints I have heard from the children themselves are that the head is â€˜too strictâ€™, particularly with regard to uniforms. Iâ€™ll leave you to decide whether that would be a problem for you
As for the undersubscription, I wouldnâ€™t let put you off. Sadly, DD didnâ€™t get in, but all three of us loved the school.