If you are moving house and about to leave your existing property unoccupied, I would definitely leave the heating on LOW rather than switching it off. With very cold weather forecast this winter, the last thing you want to happen is frozen or burst pipes, and in an unheated property you could soon get damp or mouldy patches appearing on walls or the fabric of your furniture. Also if you have a loft hatch and your loft isn't well insulated, you may want to think about leaving it open an inch or two so that a little heat can get up to your water tank to prevent frozen pipes. (And by the way, check your insurance property if you leave furniture behind, just in case of a frozen pipes incident).