I think Baz is pulling ya legs 
But in all seriousness,
I don't do anything different in winter.
However I don't have anything in the van to frost damage even though I am wfp.
I have a removable battery/pump/controller box that I take in every night to charge, a tank and a hose reel and that's it.
I drain the reel each night, if it still freezes I use a backpack for first few jobs until temp rises.
No hot water, no overnight heater.
If its too cold I don't work, but that's maybe a day or two, compared to the expense and faffing about trying to combat nature.
Sounds like an excellent idea Barry removing the battery, pump and controller, especially in the winter - any chance of sending a pic of that? Do you have the pump and controller on a removable board and does it involve a bit of faffing about with wiring etc?
None at all, I just bought one of these
http://www.ebay.co.uk/itm/Pump-Box-with-12V-Battery-and-70psi-Pump-for-Window-Cleaning-or-use-us-Sprayer-/121358493955?hash=item1c4187a903:m:mdYA7ggkT5nK37JcCPGNe7Afrom a different ebayer though for cheaper at £115, he doesn't appear to have any left for sale though.
It does need to be recharged every night, but is so easy and portable to do, 2 months use and no issues as yet, used up to 40 feet with my smax no probs.
I changed from a van to a pick up and needed to set up and get working quickly hence the purchase, I still have a 110 leisure battery indoors plus controller and shurflo pump mounted on a board as spare just incase it gives up on me but tbh am more than happy with this little unit, its so simple and has plenty of power for a days work
