Hi,
Just joined the forum, thought you worthy of my first post : )
Ive just gone self employed and had my first assessment last week with Napit. They only wanted to see one job of mine, which was a full rewire, but a fuse board or part rewire would do i think. We only spent about 20 minutes at the job, most of the assessment was at my house.
We spent about three hours going through different things at home, throughout this time he gets an idea of wether or not your capable of doing your job. He checked through loads of things- past certificates from my previous job, qualifications, knowledge of regs etc. Also had to do a quick test (10 Q's or so). Sounds official, but really no need to worry, all quite informal, he was there to see if and where any helps needed, said passing exams and experiance has already proven your competance. Hes not trying to trip you up! Basicly the more things you have to show him the better, he will give you a list of things to get, a week or so before you see him.
When we finnaly got to the job the asessor took a look at the fuseboard, made me take one of the 2way switches off to check for brown sheathing etc and that was it. I think if you just spend more time making everything really neat and tidy (not that my work isnt normally!) then you've got nothing to worry about.
hope this helps!