When I first read your post I didn't register his age, and I assumed he was more in the 8-9 year range. I think making a 5 year old "stick" something out that isn't working just doesn't make sense, not to mention you are spending a lot of money on swim lessons that are not working. I understand having a child who self selects an activity finish that session (particulary if it is a team, unless there is a serious issue), but I tend to see that as a 6-8 week commitment, not full year, and in this case you are asking him to do this activity.
I would go to the director and say that while you so very much appreciate their help in scheduling, this teacher is not working out. Ask if there is any way that one of the teachers who did work out with your son could do a morning class, and if they can't help you, go elsewhere. If they can, thank them profusely and say that you would be happy to speak with the instructor about why you made the switch. It doesn't have to be about her, but you might explain why the fit just wasn't working, and maybe she will think about her methods some.
Cat
