And here is my two penn'orth:
To find whether it is the front causing the problem, you could try jacking the car up exactly at the centre of the rear crossmember so the rear tyres are off the ground. There should be no lean
(as Jack Sprat's wife might have said 
). If there is a side to side difference, there is something wrong with the front suspension. Be wary of 'stiction' in the sliding pillar, though; give the car a bounce at the front on each side. You could measure the static length of the springs to check that they are the same (not the free length, as that would mean stripping the whole suspension down, but I suppose it could come to that).
Do the same with the rear, jacking at the exact centre of the lower crosshead tube at the front. If the car is now leaning to one side, it is probably due to mismatched rear springs. Either they have been badly made with different 'camber' (the amount of in-built bend in the spring), or possibly an incorrect one has been fitted on one side e.g one from a 4 seater. If it is camber error, the spring rates would not be affected, and the dealer's remedy would probably work, but is not ideal. The wrong spring would be a problem as it would have a different rate and would obviously need to be replaced. Have a look at each one and count the leaves and measure the overall spring height - they should be the same.
Hope this helps
Fjemog
