I don't have children at either school, but I live in the area. Bancrofts is a bigger school, and harder to get into. It's fees are typically the lowest of the three schools in the area (Forest, Bancrofts, Chigwell.)
Over the years, it seems that Forest has the most generous scholarship pot (though the lowest academic results; held down by the boys's school. In fact there were rumours a few years ago of the girls' school separating itself more fully from the boys' so its results could shown in all the guide lists in the papers etc. without being diluted by the lower boys' scores.)
I've known of several 50% scholarships over the years at Bancrofts. I think Chigwell must have a smaller pot, because I have never heard of a 50% scholarship there, the most I have known of is 15%.
Because it is smaller, Chigwell is seen as more "nuturing." Bancrofts is bigger and has a structured feel. When we visited with our DD, to us, it felt like a boys' school that had let some girls in. Bancrofts is the only school with Rugby for the boys and it feels like the 6th form boys who play Rugby get a lot of kudos. We saw beautiful fields and asked where the girls play hockey and were told they get on a bus to go to some different fields. Those fields were for the boys to play cricket and Rugby. (When you are asking kids on a school tour they may get things confused of course. They won't be intimately involved in everything.)
For us, Bancrofts felt like a serious, old fashioned place to send one's son. That said, of our local schools, all things considered, it is the one we would have chosen for our DD,1 and that she would have chosen for herself had she not decided to commute to a girls' school.