I went for an assessment and similar to yourself, fatigue is definitely my worst symptom, followed by issues with my leg left. The assessment was general questions about daily tasks, similar to what gets filled out on the forms.
I was rejected. Apparently I have more better days than bad. The interviewer also noted that I didn’t look tired at the interview. I was furious at it.
I haven’t appealed it as don’t want to put myself through it all again. I’ve been diagnosed nearly a year and find it difficult to accept it myself, so being rejected made it worse.