I used to use "Re-locate Selected" iTunes Script from Dougs Scripts, it worked perfectly, but it stopped after the iTunes 12 update.
If anyone knows how to edit the script to make it work that would be great.
I just want to update the solution I'm using now, how I got there.
Ok so after I posted originally I noticed the Tunespan answer, and decided to give it a try as another solution was messy and time consuming at the time I was on OS X 10.7.5, So when i went to the App store I found it was not compatible with 10.7.5.
However on there website the have an older version Tunespan 0.9.8.3 beta, This version is compatible back to OSX 10.5 and it's free,
After installing it and using it for a few months, I have no reservations in recommending it, it's pretty much exactly what I was looking for, The app opens into an iTunes like interface all your playlists are there it's easy to search for and sort, you can restrict what you see by location.
You can select multiple destinations, there remembered in a simple drop down menu for future reference. Choosing what to move is dragging and dropping into a temporary sort of playlist once you have what you want selected, and you pick your destination its a button press to have it all happen.
I upgraded my system to Yosemite about a week ago, it took a lot of time and tinckering to get it working as im on a Mac Pro 1,1 which doesn't technically support Yosemite.
Even after all the upgrading etc.. my iTunes library is still working perfectly even though atm it's spanned over 4 drives.
Now I can upgrade to the current maintained version which I'm looking forward to.
P.S. I have no affiliation with this or any other software company this just was the only solution that I found workable.