OK getting back to the OP's topic for now. Sorry I dont know of any way to calibrate the lines. Or even if the dealer can do so.
But apart from trying different camera view modes could it also be due to whether you have the camera set for fixed guidelines that dont move or dynamic guidelines that bend as you turn the steering? Page 519 of the Jazz online manual. Is it possible that you have mistaken a line that is in fact slightly curved,or straight but not quite parallel with the car ( as it would be with fixed guidelines ) due to slight movement on the steering?
It might be worth switching between fixed and dynamic to see if the accuracy of the guidelines changes. Or in an empty parking bay try and replicate the inaccuracy with slight steering movements. Anyone seeing you shunting backwards and forwards experimenting will think you mad of course, so give them a
This dynamic movement ,and probably other sytems on the car such as power steering, would require a sensor to detect the relative position of the steering wheel. Unlikely but its just possible this steering sensor is out of calibration and showing steering (and thus the reversing guidelines ) as straight ahead when its actually not quite true. . If you have eliminated other possibilities it might be worth having a word with the dealer.