As you will have read, I'm not suggesting that at all. On the contrary, I suggested that Part P applies to any 'installing' of anything electrical, whether indooors or outdoors, and whether it be the initial installation or replacements (or changes) undertaken in the name of 'maintenance'.So as long as you 'forget' who did the initial install you can do whatever 'maintenance' you like without notification even if the original person didn't do so or test or certify? I remember asking about such a situation before only to be jumped on by the same people who are now suggesting that someone who knows nothing about electric is ok to work on a faulty garden power setup.
I do agree that law probably has no control over 'inspecting' or 'testing' an existing electrical installation, which could be regarded as anomolous, but the moment one does virtually anything to an electrical installation, that will probably fall into a broad definition of 'installing' - hence bringing it within the scope of Part P (hence requirement for competence) and, if appropriate, the notification requirements of the Building Regs.
Kind Regards, John