Ach, everyone knows Thornden is a hot bed of sex, drugs and rock and roll, and everyone knows at least 20 pupils who have been 'withdrawn' from there
.
Must be why people scramble to get into catchment...
There's a lot of jealousy, and yes, snobbery about Thornden. It is very MC. But it takes academic pupils, and sends them on their way with a slew of A*s to PS, thence RG uni, if that's what you want.
It perhaps doesn't tolerate poor behaviour thus might not be welcoming of such pupils, hence maybe DC are advised to leave? I don't know, because both my DS's Y7 class photo and Y11 class photo deviated by one pupil apiece. Both additions to their classes!
See, where I grew up, Hounsdown had an appalling reputation!
You need to visit the schools and maybe ask about specific ones on here from parents whose kids are actually there or have left recently.
Yes, Ch Fd isn't 'by the sea', but you'd struggle to find a) an under £700,000 5 bedroom house that is b) in the catchment of an excellent school, and c) actually close to the seaside, not warehouses and docks.