I didn't go to a grammar school - there weren't any where I was bought up (deprived, northern). My husband went to a Catholic comp in a very poor area. We both have good degrees from Russell Group uni and have done well. We did both have huge amounts of family support though. My DH from a working class background, and me from a middle class background (but a single mother and no cash).
We've moved with work around the country, and made sure that when it came to kids we did not live in an area with grammar schools. We'd seen what the 11+ had done to our friends' and colleagues' kids. Fine for those who were dead cert entry, but really shitty for those on the borderline who just got in, or just missed. The 'just got ins' felt thick all the way through, even though they were bright, and the 'just missed' felt thick because they had failed at 11, even though they were bright. It became clear that extra tutoring all the way through, or private prep schools were commonplace to prepare for entry.
We moved to an area with great local comprehensive schools. The area has one 'catchment' for all the secondaries, and pretty much everyone gets into the one they choose (something like 95%). So kids in social housing get same choice of state school as those in £1m+ homes. Most schools are now academies but some still proudly describe themselves as comprehensive, like my kids'.
The secondary we chose has excellent results and is a very nurturing environment. No hothouse, no selection, yet the able kids do extremely well, and they grow up as part of the community with their less academic friends, and value them as equals.
Not lefty claptrap at all. Just good, local schooling for all. Far better spending money on this than with the gimmick of grammar schools.