A few people I know at the BBC went to the same Sigur Rós gig that I did. And I just happened upon a blog post by one of them (which is now a 404, thanks Ben), where they had included photos by another of them. And the photos are nearly exactly the same photos that I just uploaded to Flickr: three of them, in the same order.
Just shows how much those same moments (the water curtain thing and the confetti in particular) have stuck in people’s minds…