If you have pre-facelift ones they are the same as on Disco 1, the lights I mean.
Again. don't know about Facelift, but both D1 and early D2 are height adjustable, just not self-levelling. Wouldn't want anything self-levelling as yet more sh!t to go wrong! Even the height-adjustables need "exercising" from time to time to stop them seizing up!
Rusty springs? How rusty? Must be bloody far gone to be a fail I'd a thort!
Again year of model and other details might help with which springs. 5 seater may be different to 7 seater, Sprung different to air etc.
You could just ring them, I have used these peeps in the past and they have been OK
https://www.lrparts.net/vehicle/discovery-2/suspension/front-standard-springs.html
Best of luck