Esty - you expect rain? In England? In summer?
Well, the only kind of waterproof cloak I've ever seen are those capes which fishermen wear during their endless hours spent huddling by English canals; they are made from some kind of wax jacket material and are not very Elven, but you could almost carry off the Dunedain ranger look with one.
I just allow myself to get rained on because it's quite nice in the summer. But my serious recommendation would be a large umbrella.
