In any good comprehensive school you will find that there are kids keen to study and being supported to do so.
You seem to have fallen prey to the idea that London comprehensives are full of feral menace kids.
And yet on average London comprehensives outperform others across the country.
Personally I would avoid the ‘boot camp’ style schools like Mossbourne or Michaela.
But if the schools I have seen recommended above, Charter, Dunraven, Graveney, Chestnut Grove, Elmgreen, they are all schools that seem to like young people, have great extra-curricula offers, good management of different levels of ability etc.
You need a comprehensive where children if all levels are supported.
The think about it not being cool to do well sounds outdated.
But you won’t get a London comprehensive that is free of a wide spectrum of behaviour and outlook. Part of growing up is about learning to live outside a bubble. There were horrendous going’s in amongst a very small minority of pupils at my D.C. S London comp: didn’t affect them at all.