Further Cambridge's comment I realise my comment may sound a bit ambiguous (wrote it on my tiny phone when I couldn't sleep).
My daughter is at Aylesbury High School, just for clarity.
SHF does seem to be the more popular for primaries in Aylesbury to migrate to, I 'guess' the reason for that is AGS and AHS seem more pressured, more 'elitist' maybe?
As of now my daughter hasn't been unduly pressured and she comes from a primary in Aylesbury that was failing, and her knowledge has a lot of gaps compared to others that come from other primaries.
Another thing that people recommend SHF for is pastoral care, as I said above the pastoral care has been amazing. My daughter has just started her periods and there was an issue whilst at school. Luckily the fact that there were only girls, all of whom can sympathise, and amazing staff, meant it was not traumatic. If there were boys I can imagine it would have ended up causing more issues.
I went to a mixed school, which is why I hoped my daughter would prefer a single sex one (she is like me).
Of course I've no doubt that she would have loved SHF too, but she is happy at the HIgh and is not sporty.