To deactivate the frost indicator, you must press the button at the end of the right-hand stalk.
Yes, I didn't mess about too much with the controls as it was dark. I did press the button, but it gave me KPH, the oil etc., but not MPH , I need to check in out in the daylight. When I was nearly home I found if that you hold the button in for KPH or MPH, so could well be operator error.