It is hard to believe but your height difference is within the manufacturer's acceptable tolerances (at least according to my dealer).
Within days of buying my LR3 I noticed the vehicle tilted left to right. In my garage I placed a level on the floor and then on the rear bumper. The surfaces were planner. I then measured from the floor to bottom of the bumper, both left and right hand sides. I repeated the measurements at the top of the bumper, both left and right again.
My vehicle tilts 3/4" left to right. I couldn't believe it, so I took it back to the dealer. The mechanics checked all systems and nothing was amiss. According to the service rep, the is a 1" difference which is within acceptable tolerances. I expressed my disbelief, but he told me not to worry.
It has never felt right, but (for me) it is not enough to trade in the vehicle. I am concerned, however, about uneven wear after 100,000+ miles.