Filton sits just north of the city boundary, in South Gloucestershire. Everything about daily life points at Bristol — the shops, the commute, the postcode people give out — but school admissions run through a different council, on a different timetable, with different forms.
Neither South Gloucestershire nor Bristol has state grammar schools. The nearest selective route is the shared county entrance test up in Gloucestershire, sat at the very start of Year 6, which means the decision to go for it is really made in Year 5.
None of that changes what a lesson looks like. It changes which deadline you are working to, and it is worth settling before anyone commits a year to 11+ preparation.