While I agree with the opinions being ventured in this thread, I'm not sure whether they answer the question, which was, I think, "technically and legally what should we do?"
Reason I say this is that someone with an Intermediate Amateur Radio Licence is allowed to build his or her own radio (mains powered electrical), having (usually) studied the RSGB material. But then this person is not considered to be electrically qualified. The irony is that while I have been assessed as competent to wire a so-called "13A" (technically a BS1363) plug and build my own amateur radio as far as the RSGB is concerned, I'm not qualified to do so in other fields, even though it's exactly the same plug!
Why is this relevant? It's relevant because the C&G NVQ2 course contains an electrical element.. We are taught how to carry out very basic tasks such as junction boxes and FCUs and the safety aspect at a basic level and then told this isn't a qualification. Why, then, are we being taught this, if it doesn't make us competent? Well, because C&G knows you'll end up doing this sort of thing anyway and they'd rather you had at least a basic level of electrical education.
Similary, the BPEC course gives you a level of knowledge that then still doesn't make you a competent person. Not that I don't think it's a good idea, though useless to plumbers who lack the ACS CCN CEN gas certificates (pre-requisites). 'It has been designed with plumbing and heating engineers in mind and is limited to work that will NOT involve working on fixed installation of the property and addresses the following scope of work.' So you still wouldn't be legally allowed to do anything except repair the boiler, I take it?