TommyS.
It depends how cold it is.(-20/+20?)If you park up in the sunshine mid Feb onwards its usually above freezing and sometimes quite warm during the daytime.Don't camp at too high an altitude when it's cold or come 2/3 am you may be getting withering looks from your companion(s) and will find you gas soon depleated.
If it's very cold I leave my water heater and heating on the lowest setting,it does not seem to use too much gas.Modern heaters should have a flame failure device which shuts off the gas if the pilot light blows out.
If you are parking up near the lifts(The main advantage of wild camping) you may find you go back "home" at lunch so you can reasses the weather.(chilled white or vin chaud)
Good luck.
Rick
