I'm confused a you say that the work's too difficult for him but at the same time are unhappy that he isn't progressing or more appropriately, being progressed. Surely it's one or the other. Would you rather the difficulty of the work increased over time whether he was ready or not?
I'm not immediately jumping to the teacher's defence but "behaviour is touch and go", "he's a little bugger", "refusing to practice over half term" and "she repeats he needs to listen" paint a fairly vivid picture of who he is and what the problems are. You say it's time for him to start behaving better but contrary to that "Class 1 teacher had very few complaints about that side of things". Which one is it?
You asking questions of a 6 year old like, ""why aren't you going up a level?" will cloud his view of how it should work.
2:1 in numeracy is surely a good thing and a reaction to his needs. Are you complaining about the extra attention he's receiving? Is he? Would he rather sit in a larger group going under the radar without the extra effort required?
Staying at the same reading level for 7 weeks isn't necessarily an issue. Did he refuse to read over the holidays? If so it may have taken a while for him to get back to the stage he was when he finished year 1. Books can be read on many levels. As well as simply decoding, comprehension and prediction become increasingly important and he could be reading the same level books but with different objectives.
"none of your business" can be said in different ways. Jokingly, rudely, joke with a jag. I can think of year 2 children I know where it could easily be said with a smile and they would take it as "don't be nosey" and think no more of it.
What guidance do you want from her? I'm sure she's trying different strategies in school but are you after parenting tips? You've had 3 meetings in the first half a term. Whilst some children and parents do deserve and require more time than others, I think you're getting your fair share and more of their time.
Perhaps ask via email (so she has time to clearly explain) what is being tried at school to help and encourage him, how it's going and how it can be reinforced at home.
I don't want this post to come across as nothing more than blind defense of someone I have never met but I like to give my professional opinion (headmistress) and it's necessary on MN to at least suggest the other side of a "teacher is shit and my angel is hard done by" thread.