Just noticed this on gardeners site. Very basic info but very good.
www.gardinerpolesystems.co.uk/acatalog/Cold_Weather_Precautions.htmlSomething I do when below freezing is to cover the reels and pumps with sleeping bags, fill up a couple of 25-30 litre containers with hot tap water and stick them under the sleeping bags as well. By the morning the water is still warm and all is well. Heating the pure water up with an emersion heater and transferring it the morning you go to work is a good idea as well.
Simon.