I got it!
I got the letter today, less than a week after the forms reached the Teacher's Pensions Agency, so am stunned that they reached a decision so quickly. I assumed the letter was just going to be an acknowledgement of my forms, so didn't really think twice about opening it. I am also stunned that they have awarded me Total Incapacity Benefit, when I thought I would have to appeal to get even Partial Incapacity Benefit. This is all a huge relief, as I thought I might have to look for a part-time teaching post for September just to go back and prove all over again that I can't teach any more.
The advice which someone on here gave me to focus on fatigue and brain fog rather than physical limitations, and to talk about risk to pupils' safety, was spot on. I also focused on how I was unable to help pupils make progress because of my fatigue and resultant cognitive limitations. Someone out there was listening and understood the impact.
So, goodbye to the last few files and folders of teaching materials which I had kept just in case. I can have a good sort out of my wardrobe, and put my suits on Ebay. Jeans and jodhpurs all the way from here.