Iadore the schools near you if you are in an 11+ area are NOT comprehensives, they are secondary moderns in disguise.
Secondary moderns don't have the brighter kids going there to bring up their results, don't get the investment, support or best teachers. Therefore those students are disadvantaged not JUST because they were unlucky enough not to be born with the genetic ability to learn academic subjects but ALSO by having less money invested in them, getting less support and poorer teachers!
Also the 'learning styles' theory was debunked some time ago. Stop saying brighter kids learn in a different way to less bright kids it's NOT TRUE.
The major problem with a grammar school system isn't for the grammar school kids it's that it FURTHER disadvantages kids who are ALREADY disadvantaged!
And that's BEFORE you get into the issue of wealthier parents hiring tutors to get their kids through the 11+!! AND that it has an effect on university entry.
"to make sure all pupils with ability get the chance" and sod the ones without ability? Who struggle?
You keep on about kids who eg aren't good at maths but are good at English - they would fail 11+ and go to secondary modern. In a TRUE comprehensive school it's possible to have streaming BY SUBJECT so that child can be in top stream for English and a lower stream for maths (where they would get the extra help needed from a good teacher).
"The focus should be on fixing the terrible school, not giving the middle class parents in the area a get-out that doesn't require going private." Exactly!