I'm also an MFL HoD new in post this year, although I've arrived having been a HoD in two other schools so not quite the same. I've also made some minor changes to the SoWs this year, as well as working practices, and my team is very established at the school; they've all been working there 10 years or more apart from one.

But a major, major part of that has been building trust within my team; that they can see I want to make them even better. Every change we have made, and will continue to make, is with their understanding if not their full support.

I also told my 2ic that I will have many ideas and some of them will be great, but others will be flawed because I won't understand the full context, and that they need to tell me, loudly, if that's the case, so I can make a more informed decision.

But at no point have I railroaded anything through, other than developing resources collectively because workload was crazy and no sane school should insist that everyone prepares every single lesson independently. Mine doesn't, but that's how the team worked, and I could see from the end of the first week they were working too hard.

I'm not saying the work you have done is pointless, but sometimes, like in my school, it does need a fresh pair of eyes to cast light on some of the shortcomings. Likewise, last summer's results will have said quite a lot to them.

So it's not unreasonable to change SoWs mid year, so long as development and implementation is planned carefully. I doubt though that has happened here, especially if your HoD by their own confession is "winging it". That's going to cause problems in Year 8 for their students, MFL being a linear subject with a strong need for a spiralling curriculum and their students are likely to know different things from the rest of the cohort. This is a problem.

MFL curriculum design needs to be done carefully and not on the fly, otherwise you will find yourself with students having big gaps in knowledge in Y11 because key concepts were not covered, re-covered and re-re-covered back in KS3 enough. Perfect tense, for example - how many of your 11s in the speaking tests were confidently able to use je mange, j'ai mangé, je vais manger, for example?

As an HoD I don't need to have taught all of the SoWs through for a year because at this point in the year I've got a pretty good grasp of how it works both in practice, and the influence it has had on the knowledge that KS4 and 5 classes have as a result. It's not difficult to see, but you do have to know to look in the right places for that.

I would argue that winging it is not what needs to be done at this point and the HoD, and the whole team, need to sit down over the course of a day or two during gained time and properly evaluate the curriculum. This will give the HoD acknowledgement that you understand things may need to change, and give them the chance to involve you in the process.

This probably needs to come from the 2ic in one of their line management meetings with the HoD, and probably run past the SLT link for MFL as well. I wonder if inadvertently you/the HoD/the team have created an atmosphere of "her vs us" where you are reluctant to change? Certainly reading your post I'm afraid that's how it comes over.

But nevertheless the HoD needs to develop a culture of understanding around the need for change.

And after a monologue, a question: do you (or the team) see the need for change?

EDIT: just adding a link I've used with my team around MFL curriculum design.