Tried the shampoo and snowfoam from AngelWax today. Well pleased with the results. This is just after a snwfoam, rinse, two bucket, rinse and dry with their (very reasonably priced) products. I'll be sticking with them for a while. The foam looks well cool, like Ribena, and gives the snow a light purple shade on the car.
Now got to do the hardwork bit ;-)