Gammy - I have raynauds syndrome and can get white, numb fingers frequently, eg when walking through the chilled aisles in the supermarket, so a lot worse when out in winter.
I've tried umpteen different types of gloves and mitts, even battery powered heated gloves, but have never really found a decent solution (I don't want to go down the medical solution route).
For cold weather, I find that mitts work better than gloves albeit not quite as practical - at the moment, I'm
using a pair of mitts similar to these and the pair I have have individual finger spaces within the mitts. I almost always wear a liner glove (eg thin gloves for running) so that my hands are always covered and outer gloves/mitts are easier to take off when wearing liners as opposed to cold/wet hands.
For wet weather, the only thing I've ever found to be waterproof are
a pair of army goretex outer mitts similar to these and I wear a pair of ordinary fleece gloves inside - I can even wash the car with them and my hands stay dry though in heavy rain it's best to put the jacket sleeves over the sleeve end of the mitts to stop rain running down the jacket into the mitt (which means they're a little less practical and less easy to take off).
Hope you get a solution - cheers