So, I got around to reinstalling Eclipse, and fixing the usertools plugin to work with the new JOSM, but some kind hearted JOSM developers beat me to it (not really surprising, I was dragging heals) but they didn't get around to updating the .jar file for JOSM to download. This should now be all sorted, though, thanks to crschmidt!

You can get it here http://chippy2005.googlepages.com/usertools.jar and it will also be picked up by JOSM. (version 13055)