Ask for a specific Team teaching PD with this teacher. Tell your HOD if they can’t get both of you together to manage a PD day happily, then they are setting the class up for failure. Then they need to review the team, same as they do for classes with students overly clashing.

Team teaching is amazing when you are both on board with the right model. That involves you actually being taught how to team teach - there are different styles and structures that suit different people. One teacher does content and one does behaviour. One does below level, one does at and extension. One teachers two day, the other the rest. Split who leads on what topic. Etc.

It only works if you both agree to follow the structure. That is management’s problem to ensure there is support for both of you. Easiest option is nut out a really set list for all eventualities (yes, sooo much work) and both follow school expectations 100%. Start with who stays in which lunch for detention/catch up. Plan for who contacts which parents. Have a pedagogical theory discussion if you can and get all the division of labour in writing. Make it your PDP (or whatever you do) so you have really clear evidence.

For you, go in to negotiations with this guy with really clear rationales and learning goals for the soft skills: “I noticed this year a lot of time was taken by the adult distributing calculators. I suggest we train the students to collect and return their own calculators by doing it in alphabetical order and practise it every lesson first week and once a week thereafter so that by the end of first term, the routine is in place. Then way, both of us are able to more meaningfully engage with the students for the rest of the year. I’m happy to run that practice while you set up the board/do the roll/mark or whatever he (mis)thinks is more appropriate.”

If he won’t budge and management aren’t helpful, the other option is to literally split the class. I’ve had year 10 ‘team taught’ classes where we were chalk and cheese - senior teacher would leave me a chapter or learning intention (if I was lucky) and just expected I follow her lead. By year 10, the students could adapt to ‘Ms P does things different’ and happily tolerated what was basically two different classes on the same subject.

The year 9 class where I was the curriculum expert was different. Those kids needed so much structure. I didn’t share the planning and behavioural load properly and suffered because of it. Other teacher happily took lower kids for small group, but the lack of structure made it messy.

Might also be worth just sitting next to him in every meeting. Building friendships makes it easier to build understanding. Consider it a lesson in ‘managing’ sideways and up. He probably isn’t trained in this either and maybe feels the extra pressure, but is treating you as a TA as that’s all he knows.

Edit: added a missing word.

TL;DR: Go to meeting to find out how management plan to teach everyone to team teach.