4 KudoZ points awarded for this answer. Comment: "Thanks as usual for your invaluable input. I have come to the conclusion that the meaning is just that the classroom is a standard type of layout with the tutor lecturning students from a desk at the front, presumably rather than the theatre type arrangement in a seminar space. Since "ex cathedra" as Don explains has such a specific meaning when the Latin appears in English, I prefer to avoid it and go with Paola's / Sarah's lecture rooms / classrooms approach. Respect Derek"