Tripometer stalk not working help please

Hello, I’m a newbie to a Range Rover Vogue 3.6 TDV8 2010 model, I have gone through all options of finding out how to view my mpg and every method I have tried does not work, I can view the mileage however cannot zero it or see any mpg, any ideas please or is it a new stalk that I need to purchase? Thanks in advance