M8, there are lots of part P rules, however if you are an electrician, you must surely know someone who is part P? yes we cannot certify the work of another, but if that "another is a mate and sees the cable runs etc, cable sizes etc, 17 board etc, actualy going in situ, the goal posts may be moved a bit. I say this way to protect you, as obviously you may be fully competent but not on the p regs. And if you have such a mate giving you advice perhaps on his way home from work each/every other day, you will become a person whose required levels of supervision are proportionate to his experience, you tecnically will be working for your mate, almost unsupervised, on your own house, and he will then charge you for what ever is hours were. Cosha. That way you will not run the riskof Upsetting the LBC with departures from part p, as your mate will be giving you advice. if you see what I mean.
and, of course a certificate for the onsideration of his hours, it may be that LBC are cheaper, but they wont tell you how to install in accordance with part p.