When I was assessed, I did a lot of research online beforehand and was alarmed at the number of claimants had said that what was said at interview, was not what was wriiten in the assessment report. I also learnt that if you ask to see the notes written at assessment, they have to show them.
When I went in, I took a colleague (to ensure fair play) and said before we start, I want to see everything you type today to ensure what I say is accurately reflected in your assessment report, and I want an email copy. Thankfully, I had an assessor who was, not only happy for me to read the notes, but also allowed me to make changes if saw fit (which I made several).
What was expected to be a daunting assessment, was fairly good for me, but I know there are many horror stories out there.
My advice Kaz is, if they haul you in for an assessment, do as I did and make sure you agree on what is written before you leave.
Good luck