Well, its not really baffling to work out why schools which can select (be it on 11+ or faith or ability to pay) tend to top the table, is it? (incidentally there are usually faith schools near the bottom too - the ones which aren't perceived as good and which therefore have to take all comers).
Single-sex schools are historical I suppose - some GSs were founded a century or so ago.
So ... presumably you've got a table and sorted by EBacc (like http://www.bbc.co.uk/news/special/education/school_tables/secondary/11/html/bacc_888.stm?compare= this) - going down the first mixed non-selective (by any means) school has 29%.
What do you consider 'good'? If we remember that in the bad old days only about 25% did O-levels and not all of those got 5 good passes - that's a good score.
Is there any way to find out about non-selective non-faith schools' performance?
Like many frustrated parents in this country, I'm baffled at how the league tables are dominated by grammar and religious schools. Why can't school choice be much simpler? Also why are there so many single-sex grammar school?
To find a state non-selective non-religious mixed-gender school with decent results (I mean decent EBacc core subjects, not those with entertainment-related GCSEs), seems an impossible task.