Mine remains off all the time, because it is knacked.Does the start stop need turning off every time you fire up the Grenadier or is it off until otherwise re-selected? I have to switch it off every time in my Audi but a family member has exactly the same model of vehicle, in which it remains off permanently unless otherwise selected.
Incidentally for 6 years my routine was, when I got in the car I started the engine and then pressed the "stop/start" off. After 6years (because I was going to sell the car) I decided to leave "stop/start" on; that's when I noticed it was not working. 6 years of my life ruined.