Hayden does indeed have a pending court case against Mumsnet Limited. It is set to be a most interesting case.
Hayden wanted to take out a lawsuit claiming monetary damages against the MN user "ALittleHelp18" for exposing certain things Hayden did not want exposed, and Hayden got a court order to force Mumsnet to reveal the user's details. Mumsnet complied, of course.
But the user had given MN false details and, without a name and address, Hayden was unable to issue the suit. The user had given MN Hayden's former name and former address. Breathtakingly naughty.
So Hayden decided to sue Mumsnet for hosting the posts by "ALittleHelp18". Money damages are sought.
Hayden opposes self ID because Hayden has managed to obtain a GRC. However, as ScapaFlo hinted, this is currently the subject of controversy and possible investigation because during the two year qualifying period Hayden was using both the new name and the deadname, which is not allowed. There is also another problem: one of the "sponsors" who wrote a legal "witness statement" in support of the GRC was a family member, which is also firmly against the rules.
Hayden posted perfectly openly on Reddit and in Hayden's own name about how incredibly easy and quick it was to get a GRC. (And yet one complaint we hear constantly from trans people is how difficult, complicated, time-consuming, expensive and invasive it is to get one!)
Hayden wrote:
"I submitted my application on 9 April 2018, got a hearing on 2 May 2018, and my GRC was dated 9 May 2018. The process in Leicester is so efficient. I work in the legal profession [sic] and I have never known any part of HMCTS to be as efficient and professional as the admin people at Leicester GRP!
I arranged my "main" report from Dr Penny Lenihan. Like you my "secondary" report was from my GP, a tick box exercise with a bill for £28! The key to navigating the GRP successfully and quickly is to make sure you have the evidence that they want to see! So documents from the start of your "official" transition, some in between, and a few dated very recently! Passport, driving licence, and academic certificates are evidential "gold". I also padded out my application with a witness statement from myself, as well as a family member who is a close friend. The process is not laborious per se but just a little admin intensive. Get the bureaucracy right and the system can be a 'cake walk' IMO!
Oh yes I had my Charing Cross GIC appointment on 8 June 2018. I had been on hormones privately at that point for years. My medical professional asks, "What evidence have you got to show you've been living in role?"
My reply, "I think you'll find my GRC actually proves that as I need at least 2 years of evidence to get one!"
So there you have it, straight from Hayden's keyboard to Reddit.
With regard to suing MN, an anon female lawyer said:
"Few things cause me more misery and rage than people using the law in a malicious attempt to frighten people and get their own way.
Gender critical women are on Facebook, Twitter, Reddit, Mumsnet and more, discussing gender and the misogyny of trans activism etc and we are well within our rights to do so. What Stephanie has done is characterise disagreement & the refusal to bow to compelled speech as harassment... How is it harrassment. Logging in and clicking the feminism threads are not unavoidable actions.
Hayden seems to have set themselves up as a public figure and surely public criticism and appraisal comes with that role. From that angle, it's hard for me to see such a case succeeding."
(Sorry I cannot find a link to the thread but it was posted in Nov 2018.)