I do think there's enough law and guidance about the protection and need for single sex spaces and adequate safeguarding to be quite clear that using preferred pronouns and creating mixed sex spaces is wrong and a breach of existing guidance and law. As is, on safeguarding grounds, excluding parents from information about their children.
I get why teachers want extra 'gender' guidance but actually, if you piece it all together, it's quite clear.
Activist groups have been quite effective in gaslighting and brainwashing teachers, which I'm reluctantly impressed by given that teachers should be able to think critically. However, there's really enough information out there now and guidance for teachers to behave according to their role and position not least in terms of safeguarding.
The two teachers in the threads I linked to are doing it.