Many village primary schools and secondary schools as such there were once were church of England schools. Also I don't think they were called faith schools then and I wonder if your conception of a 60's school is based on present Humanist UK and NSS conceptions (i.e some kind of stern madrassas).
If my parents were doing some thing radical in the sixties by sending their Kids, not the youngest though, to sunday school you are suggesting that they were more zealous in their religion than most others.
There you go again with your tedious hyperbole.
Where have I ever suggested that your parents were 'zealots' or 'radical' - oh - I haven't, but your arguments are wafer thin unless you try to make out that I think your upbringing was some kind of extremism, which I never have. My point was that your upbringing was christian, which is hard to argue against if you went to faith school and, most specifically, Sunday School.
So let's actually get back to the facts shall we.
Back in the 60s the proportion of pupils going to a school with a religious foundation (call them faith schools, church schools, whatever) wasn't massively different to today. So approximately one third of primary school pupils were in faith schools (as we would call them now), the rest in non-faith schools. At secondary level the proportion in faith schools drops to about one quarter, with three quarter in non faith schools. The reason being that (for reasons I don't fully understand) the CofE focussed its schools at primary level so there was more CofE provision at primary than secondary level. RCC didn't do this so they had as many places at secondary level as primary level. In the 1960s faith schools that weren't CofE or RCC were so rare at to not be particularly worth discussing.
I accept that in some rare places the only available school was of one type or another. However this is typically in small villages with just a single school - and the vast, vast majority of the population (even in the 1960s) did not live in small villages. So for the vast majority of parents, living in larger villages, towns and cities there was some effective choice as to whether they sent their child to a faith school or a non-faith school. And then, as now, many faith schools required parents to demonstrate their commitment to that religion in some manner to be admitted. And of course, particularly due to the strange mismatch at primary vs secondary level for CofE schools there will be parents who chose to send their kids to a CofE school at primary level who did not have a CofE secondary within a reasonable distance.
So against that background - your parents chose to send you to a faith school (I think this was at primary level), unlike two thirds of kids.
Now for schooling - parents had to send their kids to one school or another (unless they were prepared to home learn which was very rare). So I get that sometime there was the situation of having to plump for something they didn't really want.
There is no such excuse for Sunday School which was then and is now, a completely elective, voluntary choice. There is no requirement for any kid to go to Sunday school or any equivalent religious instruction system. And even in the 60s most kids didn't go - numbers have been declining, of course, over the decades, but even at the start of that decade (1960s) I think only between 40-45% of kids went to Sunday School. Unlike most parents, your parents chose to send you to Sunday school.
So was your upbringing radical, zealotic or extreme - nope. But it was a christian upbringing unlike most children even in the 1960s who did not go to faith schools and did not go to Sunday school.
That's my point - that your parents chose to send you to a faith school and to Sunday school demonstrates that they chose a christian upbringing for you - they didn't have to, but they chose to.