Link teacher and TA in the lessons itself

Make it easier to owl teachers and the TA from the lesson itself, by either putting a link in the lesson to their profile pages, or a direct "Owl the Teacher" and "Owl the TA" link so when questions arise, you can immediately get to the owlery and owl someone. This way there's no confusion (especially on the Dutch site, where the first lessons were made by people who aren't the current teachers, which oftentimes make it hard to figure out who you actually have to owl with questions).