Hi,
I had a look today at the passages seat as well. I bought my Sporting a few weeks ago but only on Sunday I sat for the first time on the passengers seat. Indeed it's much higher than the drivers one. The frame that sits between the seat base and the runners is different, and much taller. I would think (not tested) that when you can get your hands on a left hand drive height adjuster part you can swap, but not sure if the left and right seat are the same in LHD and RHD models.