above all spot on mate, the only thing I would add to it is that do not on any account, BULL S**t . if he asks you a question, and you dont know the answer, go straight to your books which you have to have with you for an NIC assesment , and go to the answer straight away. If you dont know the answer, there is no shame in that, but not knowing where to find the answer will raise serious questions in his head, obviously negative.
Obviously he is gonna ask you questions relevant to the jobs you show him, and he can ask a lot in three hours. so PREPARE PREPARE. Dont let him catch you out on ANY safety issues at all. Dont let him catch you out on any thing thats basic, like wiring routes. Get yer nose in your books, ask him questions!! he is there to help. Attitude is important too !!.Determination to get it right, etc.
Dont balls up your numbering on the CU, are all the correct labels there ?. If he thinks you are at all dodgy you will not pass. I know our peers on here say that they want your money and you will pass, but you breach any of the main safety issues then you will not. He will be making notes as he goes, just ignore this. Make sure that he is not collecting evidence of bad workmanship or breaches of the regs, part p etc, that bit is up to you. You can see that passing is down to you.