Hi,
I can only comment on St Eds/Canterbury. Check the performance of St Eds vs Rochester as I think they might be far apart.
St Eds is a lovely school and we have gone through the admissions process but decided it wasn't for us. Some of the buildings are very outdated, think Bletchley Park! Mobile classrooms that even the state system has ruled out, the swimming pool is outdoor, considering term ends at the beginning of July how many weeks would this be used for, although there does seem to be work ongoing, my daughter said there was a roof going on the swimming pool. The Junior school playground was uninspiring to me.
Things to consider.
Canterbury is a lovely city with diverse housing stock, traffic being a walled city can be horrific, and a simple journey that would take 20min off-peak can take 45 mins peak, St Eds is on a busy road with only one way of getting there with a tiny lane to turn down into. Up a very steep hill overlooking the city so walking in the winter from town is a mission.
That said they do have school buses and collect from local stations and routes.
I found the admission process cold, the school staff lovely in the Junior School, recent rapid change in Head . The entrance test for 11+ was an informal interview and a "quiz" sat at our kitchen table, so great for children that would find sitting an exam too much.
Canterbury is a small city, well-connected to London, High Speed, and Slow service to London. Coast is 20 mins away, loads of buses too. Handy as children get older.
There are 3 Universities, and many private colleges, so loads of diversity, students, and academics which gives it a nice vibe. Many places to eat.
If you want Rural life look at Bridge village. Or the villages close the Ashford on the High-speed line Wye, Chilham, Chartham. Ashford to London is 45min from Ashford.
Other schools to consider.
Kent College - Canterbury they are opposite St Eds and often align open days. Kings School Junior, this is the other side of the city so the depends on where you live. Senior School is next to the Cathedral.
Or Ashford School which is the senior school is walkable from the station the Junior is a drive out of town again there is a shuttle bus from Senior to Junior vice versa.