I am working with some TAs who are really behaving in a very undermining way in my lessons and actually making the lesson quite difficult to teach - not exactly the purpose of them being there! One called out to "correct" me today on some information (she was not correct) and then cornered me after the lesson to inform me I hadn't differentiated adequately for some of the children (which in fairness was true but then I only took over this class today.) They also are very assertive with discipline and this can make matters really confusing as sometimes I'll give a child a warning then find out they have already had one. I know I need to speak to the TA in question, but I am a bit worried as I'm assuming this is how they are used to behaving in lessons in the school and I'm not sure how to gently say that I want them to back off a bit. Truth be told, I'd personally far rather teach my lessons without "support" but that isn't an option. Or is it!?