The spring is all that should be holding the car up to level. Everything else just follows freely, or it should.
So, you either have a broken spring on the low side (or possibly a shorter one - from a saloon?) Or something has seized on the high side and preventing the car from sting down to its correct level.
If you get the springs off, check the part number labels, if still attached, or the coloured paint spots if the label has gone.