Thanks for the replies everyone, much appreciated.
Odd though - Risk and Illuminati and Dune Adventure Game were definitely all failing for me when I posted, but the first two are fine, as are the other random links I’ve clicked on. I promise they were broken when I posted! 
Dune Adventure Game is still definitely not working though. See vassalengine.org/mediawiki/i … _game.vmod which isn’t correct.