Those don't look like factory springs, the leafs are too thick and not enough of them, probably the springs that came with the axles, even still think springs first. Even if one side of the Landrover was that much heavier than the other causing the lean it could be corrected with the right spring arc, which can be adjusted. As for the heater... One of the first things I did with mine was rip out the heater, I used an after market 3 speed AC fan motor and squirrel cage from a chevy van then a heater core from a full size Dodge. That said if you want simplicity you can buy NEW heater kits from Landrover parts places I just didn't think they had the capacity to keep heat in it with no floor mats or insulation up in the great white North. lol. Oh yeh, I also threw away the fan shroud recently they just get in the way of servicing things, I had removed it years ago and kept it in case I wanted to reinstall it. Never found a reason to put it back on.
After looking at the pics again the front ones are Landrover springs, not sure about the back, how many leafs in the rear ones?
1971 series 2a 88, series 3 trans, Fairey OD, owned since 1978.