I spoke a Jaguar mechanic , and he pointed me to the fact that the brake line in the left wheel well on our x308's is to close to the bodywork , and creates rust at that location.
(Behind the shock absorber)

He told me only on the left side , and sure enough when i checked it was only on the left side where it starts to rust badly...

Bend the brakeline away from the bodywork a little to prevent this from happening in the future.