I also dont think I've ever heard of any 'Pay 2 Plumb' scheme's.
A full plumbing qualification takes fours years (not 18 months for pilots) and requires an on-the-job apprenticeship. In these economic times, most plumbing apprentices don't get paid for this so yes, "Pay 2 Plumb does exist and will continue to exist until their is a shortage of plumbers..
Do teenage wannabee's still believe in the tooth fairy and Santa Claus? No? Why still believe that an £80k course will get you a job? Here's a harsh reality - you can't have everything you want in life so make the best of what you've got.