@WinterDeWinter Your analysis is very accurate and consistent with what we saw and heard about at Tiffin Girls.
@WimMum2015 - "Their DD and TGS recognized that her time management has been an issue. A teacher actually sits with her once a week to help her plan her time." This is SEN support. Of the few comments from Year 9/10 parents you reference, there is already a number needing tutors which we would find concerning. See the SchoolParrot website for other student reviews.
For highly intelligent girls, challenges with time management, self-monitoring, and organization are Executive Functioning difficulties that are symptoms of ADHD/Autism/Twice Exceptional/2e. Girls mask and get diagnosed much later than boys. See Chris Packham's powerful documentary on BBC 2/iPlayer Inside our Autistic Minds where it was quoted that "highly intelligent autistic women are eight times more likely to die by suicide than nonautistic women.
Neurodiversity is important and should not be overlooked. To get a well-rounded view of any school, you need to look at the mental health and SEN provision available (should your daughter ever need to use it), not just the grades/sets and clubs.
Due to waiting times at CAMHS/private medical professionals, costs, and cuts in education and local authority funding, girls may not get a timely formal diagnosis, and therefore the appropriate support EHCP/IEP from teachers at school/during exams.
Depending on the A-Level route a Tiffin Girls' student takes they will need Grades 8/9s in certain STEM subjects at GCSEs to progress to the 6th form. We know of students that left pre and post-GCSEs.