Ian,
I don’t know what your budget is but you should check out Arc’teryx. I have 2 of their jackets (a hard and soft shell) and wear them nonstop. They aren’t made specificially for fishing (I think more for mountaineering and skiiing), but they really get the job done on the river.
My hard shell jacket is completely waterproof, water just falls off, and the soft shell is warm and windproof.
Give them a shot – it’s expensive stuff but my 5 year old hard shell that’s worn daily during the winter still looks brand new. I don’t think I’ll ever buy another brand (or have to).