I did read the response. It says:
"ATL believes that PSHE and SRE should be compulsory in all schools so it can help young people to become resilient, well-rounded, and confident adults."
"ATL believes teachers need help to become confident in teaching PSHE in their schools through better initial teacher training in PSHE, ongoing continuing professional development and up-to-date guidance and training."
"Schools and colleges should be proactive in their approach to creating trans-inclusive policies for both staff and students and they must create an environment in which everyone, whatever their gender identity, feel equally welcome and valued, and in which transphobic, sexist attitudes and behaviours are challenged"
Nothing in there about introducing compulsory gender diversity training, just that they believe schools should be proactive at combating transphobia and that teachers should have the support and training to do this.