The lean is a feature that the (RHD) XJ came with from factory
Pretty much common, lot of info on it Google "Leaning tower of Jeep", and one recent thread on here from me regarding this should pop up, also GoJeep's site shows info on how to correct it as well, etc). Besides all the heavy things being on the same side (Battery/driver/spare tyre) causing a 'tendency to lean towards the driver-side', it also has to do with a design flaw. Apparently the left side sits somewhat higher for something (forgot what) to clear the front diff housing. And this was not compensated for on the right side, that's how I came to understand this lean. Several options to correct, from which the coil spacer is a cheap one. Not sure, but XJ front coils might need to have a slight difference in length between left and right (at least those I got from Oldon are
. Not sure if this goes for all coils though. Suspension guru's might have more input.