Surely the only thing that matters here is whether or not you have enough time to complete your responsibilities during working hours… plus in my mind approximately 5-7 extra hours at home (or arriving early/staying late after ECAs/CCAs) per week is reasonable.

For example, in a brand new school there’s so much to do beyond classroom teaching that a lighter ‘contact teaching time’ is essential. However, in a well established school with lots of Teaching Assistants, resources ‘on hand’ and solid ‘well-established’ planning requiring only minor tweaks, then a higher ‘contact teaching time’ would seem fair.

Each school will be different, and anyone looking to move just to ‘teach less’ is not someone I’d want as a colleague in my team.