Bump, still looking..any trial welcome.
OK - I'm going to say this as gently as I can.
You've been posting for over 15 months now. You started out not giving a location. You've said barely a word about what you've actually done or where you've worked.
Sandamoss offered you an opportunity. You said he couldn't "promise" you work. Well, if you want it badly enough, you'd take even that. Nobody is going to promise you a full-time job unless you prove you're a worthwhile investment. With the background you've described, you'll cost an employer more than you'll earn him right now. He will need to invest a lot in you before getting anything back.
You said you had no experience in plastic. Billy gave you a very good, short set of instructions. That's literally all you needed. You could have gone out and bought a length of pipe and some fittings, had a practice, and hey presto, you can work plastic!
15 months is long enough to have done an introduction to plumbing course at your local college. Some of them offer a basic course as an evening class. You could have taken acecharly's advice and advertised for small jobs on your own.
Right now you could have been posting that you'd done a Level 1 course, done some small jobs like tap washers, drain unblocking etc. and were confident with both copper and plastic. All of a sudden you'd have been a much more interesting candidate.
This is a hugely competitive field to get a start in. There are hundreds of posts on here by trainees / apprentices looking for a start. Jobs will not come to you - you need to chase them proactively, and set yourself apart from the competition by showing that you are keener, more motivated and have a better foundation knowledge than them.
Of course, it may be that you've done all of these things. In which case we're back to the same problem as your very first post - you need to give us more details!
Good luck, but remember,
you have to make this happen!