I don't really understand all this NVQ malarkey, being C&G qualified decades ago, before NVQs thought of! What I do know is - there are a lot if semi qualified guys with no chance of getting a proper job, and if the course provider is being obtuse, steer clear.
SE guys are constantly being asked to help complete portfolios in return for free help. In truth, there is normally no benefit to the tradesman, and plenty of downside. I have done it a few times, but only for those who know me via a friend. it is, frankly, a pain.
However, if you can get qualified, then there is a future to be had, just be careful how you spend cash, especially if you have to end up borrowing to fund it