Update!!!
I resigned today.
It turns out, behind my back, in my referral to occupational health my manager had lied on paper saying I was late for work, took short notice annual leave which inconvenienced the department, left work early, was antagonising coworkers, and a bunch of other factually incorrect statements.
I found this out this morning at my OH appointment when the poor adviser was reading them out.
Asked for a copy, sent a very angry email off with my resignation letter. It's basically constructive dismissal. They wanted me gone so they can re-recruit into the post.