Ekklesia's response is here (http://www.ekklesia.co.uk/content/news_syndication/article_06119altern.shtml). There's also links to a number of previous articles on the question.

They're a good bunch of progressive Christians. I disagree with them on certain things, but that's usually because they have a very UK-centric view ("don't fly on airplanes, travel in other ways"... is a little difficult to apply in Australia if I ever want to see my parents again.)