Hi XF owners. I have recently become the owner of a 2010 XF 3.0D 240bhp Premium Luxury and love it! I have noticed that fuel seems to be leaving a trail down the rear wing, regardless of whether the tank has jus been filled or not. The filler cap seems to work well and the gaskets don't appear split. Is this a case of buying a new filler cap or is there likely another fault somewhere? Appreciate your help.