I don't know why, but I always lump primary and junior school together in my mind: if I say one I almost always mean both.

My time at a Catholic grammar school was 'interesting'. Apart from the daily assembly and a couple of RI classes a week there was little religious bent. Some teachers opened their lessons with a prayer, but these were the minority and it was perceived as more of a quirk of that teacher than anything else. The headmaster changed in my second year and it certainly moved in the direction of being less authoritarian than it had been before. There was physical punishment in the form of a leather strap on the hands, but that was mainly for failing to do homework or on occasion behaviours. I do remember one lesson in particular where the teacher was late and so people started talking. When he came back he complained about the noise, lined us up outside and spent the entire forty minutes walking along the line strapping each person in turn. Sounds bad, I know, and definitely part of the school culture, but religion based? I think not.