I was trying to take the heat out of the debate and be even handed - but seem to have failed :+(
My experience, admittedly of secondary rather than primary, was that (averaged over the school year) the working week was highly variable but not excessive.
Teachers tended to split into "get home before the traffic, but work in the evening" and "get it sorted at school and then the evening is my own" - and yes there was extra stuff sometimes (parents' evenings, am-dram, sports, whatever) but also quiet weeks during exam periods.