Don't know if this is useful to anyone but I was in Semi-Chem this weekend and on their travel stand they have packs of 2 adult ponchos for £1. Just in case anyone else likes disposable ones. They do say reusable but judging by how thin they look I would think you could use the for a day and then bin them. Oh, and they also have a waterproof phone/card/keys pouch. I bought one (also £1) as an extra, although I do like my "box style" one with a rubber seal on it.