I suffered all of last winter...and all of our useless British summer, in a windproof but certainly not waterproof sailing jacket.
Well, my lovely other half bought me a new jacket and I LOVE IT!!! I would fully recommend it to any dog walker! It's slightly longer than a standard coat so keeps the top of your legs & bum dry, the hood has a proper peak so your head and face is sheltered...big bonus when you wear glasses and are rendered virtually blind when rain beads on your specs!
And the best part? The silly wotsits have guaranteed it 100% waterproof for 3 years!! So if it does happen to leak in that time I get a brand new coat! YAY!
Seriously, if you are without a waterproof coat...get this one!!
http://www.mountainwarehouse.com/womens/clothing/waterproof-jackets/hurricane-womens-long-jacket-p6927.aspx?cl=BLACK