I had naively assumed that the non-protected status of 'being non-binary' was already established (I was confused by the 'non-binary passport' case!), so this was interesting and welcome news, thank you for posting it.
It's a well-written judgment and positively influenced by FWS (making it, I hope, the first of many). It's crystal clear now that, in law, sex is M or F only, and 'proposing to undergo' in Section 7 means only actions or proposed actions within the specific GRA framework - someone who does not intend to live in an acquired gender which is the opposite of their sex does not qualify.
NBs are still protected from harassment at work as are all of us, and the tribunal considered the harassment claims and rejected them as trivial/accidental/non-malicious/IT glitches etc etc. I can see that the claim could have succeeded if there was persistent gratuitous misuse of name and pronouns, in a way intended to distress, and if the employer did nothing about it. I think that opens up a different angle on the topic (enforced speech, protected belief etc), so will save for another post...