One question I asked that questions my computancy was the water bonding. My gut instinct as a competent tester would be no it doesn't need bonding as the incoming is not a conductive material- but Sod's law if I didn't ask the question the niceic would be as misery as you.My suggestion would be that if you have to ask these questions you're not yet competent enough to be carrying out such work unsupervised. I would seriously consider getting some more knowledge and experience under your belt before carrying out your own work.
My guess however would be, that you won't take a blind bit of notice of what I've just said and that you'll just plough on regardless feeling secure in the knowledge that if the NICEIC say you're competent, then it 'must' be true.