I did the level 2 6129 plumbing which covered sheet lead using bossing sticks wedges etc. Which was discontinued. But had to do all the practical in the college 1st 2nd fix bathrooms ,soil pipe installation, air testing, guttering, open vented hot water systems, services valves isolation, etc. But ok a port folio was made as we progress. But at the end I'd say it's what you and yourself make of it.
With a foot in the door. It doesn't mean you aren't a qualified plumber
NVQ I think is quality, but you'd always be bargaining to keep a good rate and pay in most places, and are likely down the hill .. say I'm happy fortunately to work with a qualified gas engineer with C+G 6129