Really enjoy all things about owning & driving Jaguar. My XF 3.0 D S Portfolio is my third after owning two trusty STypes previously. However, my XF makes a sloshing noise from rear when braking and full of fuel. It has developed a rattle (near side of dash) I think it is air vent related. Fuel filler flap has on four occasions refused to open. Still under warranty. Going in to dealer next week. Anyone else had similar?