The 1265 hours figure is Directed Time, most of which is teaching lessons.
Even if you ignore the lesson planning, after school detentions, after school revision classes, phone calls home after school and meetings with parents, just think about the marking.
A teacher may teach 200 different children in a day. The teacher has to assess progress and give feedback to students. Even if the teacher spends only one minute reviewing and correcting each piece of work that's over 3 hours a day. And then there may be homeworks to mark too.
Okay, the figures vary from day to day but I know from experience that teachers work nearer 60 hours a week. I'm in school for 10 hours a day - almost always 'on duty', and I work most evings at home and every Sunday.
Yes, teachers have good holidays but I have a long list of tasks to do over the summer.
I agree that other professions work hard too but i wanted to address some of your misconceptions.