Firstly, if 1 twin got in the top 500 then my understanding is that they should have a very good chance of getting a place.
Secondly, lots of bright children don't manage to get into the top 500 or so at Latymer, but then go on to get places at academically selective Independents (or do very well at state schools) so don't be too despondent for the other twin.
Here a number of schools which take girls. There really is quite a range and they are very different. Note many of them closed for applications yesterday.
Have been closed to applications for a few days:
Channing
CLSG
Highgate
Deadline yesterday:
Francis Holland Regents Park
Godolphin and Latymer
https://www.godolphinandlatymer.com/adm ... /11-entry/South Hampstead High School
Queens College London
https://www.qcl.org.uk/admissions/admissions-11-Waltham Forest/Essex direction and could be open for applications:
Forest
Bancrofts - is still open for applications
Chigwell
Also look at:
St Margarets Hampstead
https://www.st-margarets.co.uk/More House
State schools that people often move close to to get a place include:
Fortismere
Alexandra Park School
However I'm not sure whether CAF can be updated now and that would need to be checked.
Hope this helps. It's an attempt to answer your question.