When I grew up, there was one religion. You got it in assembly at "secular" school. We had a Christmas play, and I even won Bible prizes, though I never went to Sunday school or church. Except of course for the outings and parties and later, discos in the halls of the various denominations.
There were also Catholics, an "inferior" religion, whose practitioners lived parallel lives to us in the same community. Some even went to our schools, where they were excused the RE study period.
I also envied my Catholic pal's ability to get his sin slate wiped clean every week as I waited outside the chapel for him. I assumed I would meet some bean-counting angel with a very long list when I died.
Other more "exotic" religions were never really discussed per se, though they were mentioned in passing in history or geography classes as something foreigners believed.
It's amazing how none of it stuck really, I grew up in an area stuffed with churches, half a mile from Holy Corner!
Holy Corner - Wikipedia