Are you in Kent OP? I actively avoided moving there as I knew DS wouldn't get into a grammar school.
He's bright enough, and working beyond expectation in English comprehension (he's on the borderline of working at and working beyond in SPaG) and working at expected level in all other areas.
But he has ASD and falls apart in test situations. I didn't even bother putting him forward for the 11+ as I knew he'd freak out and fail. After many practices he's now happy to take his SATs next week, in seclusion, with extra time and movement breaks, but we wouldn't have got that for the 11+ as the school had to provide evidence that it has been used before. Of course it hadn't, as he's never had a bloody test like that before!
As I'm active in our local ASD/ADHD community support groups, I see a lot of kids like this - really bright, but the grammar schools are only accessible to the few who can handle the exams. At that age many of them can't, so it weeds them out early on.
Luckily there's a fantastic academy round the corner from us that DS is going to. But the concept of grammar schools makes me feel uncomfortable. My parents didn't put me in for the 11+ even though they knew I'd pass it purely because they both failed and were stuck in secondary modems. They both ended up as senior managers, with the vocational equivalents of masters degrees, but they both said that they spent their teens known as one of the thickos from the comps. And that attitude even prevailed amongst the teachers at the time (1960s) - that the kids they were teaching weren't really worth it.