I tried the shift key and it caused problems - unless it was a complete coincidence, iTunes forgot the location of all my files, and wouldn't find them again, so ended up restoring from a back up - now my library always has "previous iTunes library written at the top which bugs me but irrelevant to this discussion.
However something that is relevant to this discussion is that after my duplicated playlists I decided to go back to the conventional "plug it in and sync playlists" method for music and turn match off - much easier? Well no.. Because my phone wouldn't sync via cable anymore. 1 full restore later it's back up and running - annoying but fine- its ok now.
BUT I had not only turned on match on my phone, but my iPad, mums phone and dads phone. Last night went to sync my iPad - it doesn't work - had to do another full restore.
Tried mums phone- same, I can make a pretty accurate educated guess about dads!
I love my apple products but am SICK and tired wasting my time searching for and implementing solutions for problems that shouldn't happen in the first place. I still have 2 phones to waste a couple of hours restoring and match now remains firmly turned off on all of my devices because I'm so scared of the damage it might do :-(