When MN took on the government over Bounty, the whole stick was that 'women on a maternity ward are not vulnerable'.
It was almost a case of demonstrating the various ways in which Trusts hadn't considered safeguarding when it came to Bounty and why women WERE vulnerable and acted in ways which they would not normally do so AND how widespread issues were, and how no complaints didn't necessarily mean there wasn't an issue. Its just that women didn't feel able to complain or raise an objection. Hence this is why they were vulnerable...
You can do this, by asking certain questions about how institutions have done risk assessments for certain situations that might involve a vulnerable person via an FOI request.
What I suspect you will find is an absence of risk assessments, and any policy there might be, will be based on one sided thinking.
You have to force transparency on how they have come to decisions like this, and ask how they have assessed the needs of both vulnerable women and transpeople and come up with said policy.
Its all in the wording as to whether it works.
But the basis point is getting them to some how admit that whilst they might be assessing the needs of transpeople they have not considered its impact on vulnerable women.
Its essentially about pointing out, whether they have fully compiled with their responsibilities via the Equalities Act that protects on the basis of sex as well as gender.
The intent is to start growling at institutions that you know all about the Equalities Act and how they might be breaking the law and almost hint that they have a liability that they need to sought out pronto.
These institutions do not want a legal case and will try and head it off.
Yes a legal case would be very helpful, but getting institutions to be seen to have their pants down on safeguarding, is more to the point.
We are talking schools - have they assessed properly the bodies going into schools and whether they are suitable.
We are talking hospitals - and potential rape / sexual abuse victims
We are talking plastic surgery etc - and whether young people are getting a range of information from a range of sources and are able to make properly informed decisions which are accurate.
Identify who is most at risk.
At the moment, the situation is the idea of the poor trans community where everyone is a good guy. That's never the case in any situation. There are good and bad in every community and their are people with conflicting interests which might be putting the vulnerable at risk for their own political agendas and profit.
As I say, I don't think you need to necessarily get as far as going legal. Just scare people and make them realise they are responsible if they don't take their safeguarding seriously in this area and something does happen on their watch or they might face a legal challenge.