It's not £225 just for the washers, they come as part of the winter pack which includes heated seats, and I think a low washer fluid warning.
I'm not 100% sure how the Mk6 washers work, but on every other car that I have with, they have been electricly heated nozzles that are on constantly with the ignition regardless of the temperature. They will not stop the water in the bottle and the pipes freezing (the screen wash contains and anti freeze agent) but do stop the water in the nozzels from freezing due to the 60mph wind chill that reduces the water temperature far lower than the screen wash can cope with.
Nor will they help with de-icing. You'll still have to do that the old way, or like me, use one car to bloke our drive entrance, while the other car is left running doing all the hard work for me.