From Tavistock Times 12.2.15
* Replace key battery every two years, including in the spare. A replacement typically costs between £20 and £50 for a blank electronic remote with a blank transponder and a blank keyblade. Allow around £15-£20 to programme it and cut the blade – from a main dealer, typically £70-£1`50.
* In autumn, use a lubricating spray on the keyhole, such as a 3-in-1 oil or GT85 Teflon spray.
* If lock is frozen, hold a hot-water bottle over it and then use WD40 or GT85 to disperse the water.
* Use chalk dust on the door rubbers when oiling the locks.
PS from The Shed: We tried Googling for the difference in performance between WD40 and GT85 and there is not much, but GT85 is a newer formulation and some think it superior.