+1 for military surplus.
Johnson of Leeds, attend all the big rallies (oop North, anyway), huge army surplus. In the worst of weather, I use a German fleck tarn jacket over my normal kit (which is pretty good anyway, hence its only in the worst weather I bother with the German kit). It's goretex, it cost me £20 6 or 7 years ago, and has never leaked. Bargain.