Mitigating circumstances- medical

Hi,

I was due to take FR on Thursday but have been in hospital for the past week and having a small surgical procedure done today so was wanting to apply for mitigating circumstances and get the exam moved to September.

Has anyone done this from a medical POV before and what documents do you usually need? I’ll be issued with a sick note for my job anyway but do ACCA usually need more like an official letter?

Have seen some people have been rejected so just want to strengthen my chances of them accepting me

Any help greatly appreciated