I'm not sure how you know what we were taught. As I said poor innercity area, most of us first generation born here (Catholic school and majority of parents were Irish, Polish and Italian but we did have some Spanish and Greek children) and to get virtually 50% into grammar school was pretty impressive whatever you think. It wasn't unusual for the reception teacher to be coping with children who knew no English, my best friend was Polish and by the time she was in year 6 she would spend some time helping when children in reception were distressed. I know our pass rate was higher than the private school that was staffed by nuns from the same convent, our nuns were a bit sinful and full of pride about that.
I have GC at primary school now and I know what they are doing. I'm not sure how good their maths/arithmetic would be compared to ours without metrication and calculators. We could cope with times tables for 12/14/16/20 as we needed it for calculations. English grammar was also very well taught and history well we did English and Irish history (as majority of us were from Irish families and several of the teachers were Irish.) Remember we didn't have any of the aids that schools can use now, no computers, not being able to watch history and geography programmes so that children now can access.
You are totally wrong about the kids who didn't pass the 11 plus, they almost all went to the local Catholic secondary mod which also had good O level and CSE results, I knew some went on to teaching/librarian/nursing/skilled jobs like mechanics.
I wonder how many equivalent schools would get similar results now?
I don't actually think beating education into kids is a good thing but the reality was strict discipline was the only way they could teach 48 kids. I think discipline at home was different as well, again for us in a Catholic school with families of 10plus children not unusual and the biggest family I knew was 23 kids, mothers also had to run a tight ship.
Not all schools were the same just like now so to decide what my school did is rather arrogant of you. You sound like you really want to put down education in the 50s and 60s but maybe there is something to learn from it, not a replica but some ideas. When I listen to Katharine Birbalsingh I think her philosophy (minus the beatings) is not that different to the nuns who taught me.