I've covered this upthread. Yes we did, went through various selection processes, tutoring, the works. Breezed through private school entrance exams, didn't get through the super selective grammar.
We did the sums. We looked at inflation, interest rates, mortgage, Labour policy commitments, fee rise projections, and the need for contingency, across two kids. We had a choice between me changing jobs (probably fairly easy to do) but being a great deal less available for both our kids, less ability to take part in clubs etc after school, a lot longer in wraparound care for our youngest, and a mother who was fairly stressed and miserable. And we decided it would be the wrong option for us based on the choices we had.
We didn't hate the school. I was really nervous as I'd absolutely hated the other comp we looked at, but this one has pockets of real brilliance, areas that need significant work too, areas that still really worry for me. And the head is seriously impressive.
And DS loved it. It didn't have the wow factor of some of the private schools with amazing facilities (though tbh there were one or two that weren't that impressive) but after the open day and the tour day he preferred it to our nearest private option. He confessed later that he was relieved he hadn't got into the superselective because he'd have felt obliged to go there but he loves his school and has really thrown himself into school life.
Did I want the "biggest mix possible"? TBH we didn't have a great deal of choice, the options available to us were the options available to us. In some ways it's not a bad thing, I particularly like that the school has such a strong ethos on SEN and I know a couple of kids in higher years who have been so well supported there.
If I'd had a daughter I daresay we might have gone for the "safe" option, though I did surprise myself during the whole process how open I was to thinking differently about schools I'd previously said "never for my child" about.
I agree that there are a lot of sharp elbows resisting admissions reform, but I won't stop campaigning for it! Our own experience has underlined what I already thought about just how fucked up it is.