A year or so ago it was an OFSTED inspector reviewing a school in Salisbury who pointed out that it was a SECONDARY MODERN he was looking, despite the school's claim to be a comprehensive and thus would not be judging it in the same way as a true Comp, seeing as Salisbury creams off the more academic DCs, albeit via a HOST of private preps, to 2 single gender grammar. It would be fair to say that there are a lot of state parents in the area who don't even 'allow' their DC to take the 11+ on the basis the odds are so heartily stacked against them. And you DO have to ask to be entered for the exam.
Personally it surprises me that the bulk of the Salisbury parents don't rise up against this iniquity in their midst, skewing their DCs education, but perhaps they're so middle class they assume their DC will OF COURSE get into the grammars.
Fwiw, I went to the girls grammar in 1973 but believe me, it's a WHOLE different kettle of fish these days!