Claig - no, Bexley parents understandably see the current choice: coach your child to study with the top 20%, or let them fail and study with the plebs. There is very little difference between grammars and non-grammars, and even private schools for that matter, other than the young clientele.
If I was a Bexley parent, I'd try my damndest to get my kid into a grammar. But then, I'm middle-class and educated myself, so phooey jr isn't moving up in the world, but maintaining their birthright. Grammars are packed with middle-class kids with parents who have the savvy to play the system.
Grammar schools do not promote social mobility one ounce and by their very nature are divisive.
Do all the pro-grammar posters think that academies are a good thing then? A failing school I know (non-grammar, therefore it's clientele are the 80% of kids not in grammars) is converting to academy status. This means it will be in charge of it's own budget, and will not contribute to council-run SEN services which are reliant on schools to survive. It can become selective. Given the choice, no school would accept kids with special needs, poor kids, kids with difficult homes. It affects their results, which makes them 'fail'.