I object to them calling themselves the "Green" party. I studied environmental science; our Chair, Dr Andrew Porteus, specifically rejected the emotion-based, ideologically-driven and environmentally-illiterate rubbish that eminates from them and their ilk.
As for their stance on defence - it's archetypal Loony-leftism (noting of course that the real communists in this world operate some of the most brutal and corrupt regimes and are currently arming themselves to the teeth).
I don't disagree with their desired end-points, Utopian as they are. Its just that when the diagram of how to get there is an empty box - then that is a big clue as to the likelihood of them being successful in achieving their aims.