I think para 3 is the most significant one.
Now there was no question of an in-service award in my time so I know nothing of that detail. I was downgraded from A1 to A2 some 20 years before I retired.. I was required to sign a letter acknowledging my downgrading. I doubt that procedure has changed.
You have a date. Make a subject access request for your medical notes at that time, or ask them to show you the letter you 'signed'.
Also contact the RBL, they will give you better, and current, advice than we sweats on pprune.