Ben, Welcome to the forum. Was glad and intrigued that you used the word team. I like it.
I think if you work it one paper, document no matter what your assignment that you could pick up where you left off. I think you'd need that; unless your memory is better than mine. I'd have to be meticulous. I think it is important to print the worksheets and have them available. I think you can still copy the lessons and exercises; put them in a ringbinder and if possible take them with you.
I'm not familiar with the military in UK; however, here they would provide treatment and not have ramifications (be kicked out) depending on the severity. I don't know "where" you've been in terms of your duties, but does your depression have a post traumatic stress component. If so, it's important to get that treated and be cognizant of and understand the downward spiral that depression can bring.
You'll notice from my posts, I post alot, have opinions. If they are helpful GREAT, if they aren't - it's okay.
You can also copy the extra sessions at the botton amd even though the "exercises) are not open until you complete a session, they are explained in the session. You could create your own form or method of documentation.
Welcome and post when you need to.
Thanks for serving in the military, you have my upmost respect and gratitude!