It can be moved. Just need to find another place, extend the wiring and air hoses.
Or fix any possible leaks; the gas filler gasket and rear spoiler were the spots on my XF. What the Mercedes dealer does to fix the problem is turn the unit upside down and put it in a bag. There is is a kit for that, but probably won't work on the XF, because in the Mercedes its mounted vertically whereas the XF its horizontal.