OK, for those who don't know WTF I'm on about...
On my disco the rear springs were naff, and the newly-fitted (and expensive) alloy petrol tank looked rather closer to the ground than I liked. Also the handling was a bit softer than my preference... what I wanted was about 1" lift and about 10% stiffer springs...
study of spring rates soon decided that there were many options for the front end, this being a V8. In the end I settled on NRC2119 (partly 'cos it was what I wanted and partly 'cos Paddock had 'em going cheap). They're diesel spec RR/disco front. There is, too, a taller/stronger one which I assume to be HD diesel spec.
Back ones presented more of a challenge, not least 'cos of a lack of accurate info as to what's actually fitted to the disco rear as standard. In the end I went for the highest-rated standard rear springs I could see in the list, which are D90 HD rears, RKB101230 and RKB101240. These turn out to be about the same height as the disco rears, but I suspect still slightly stiffer. They're dual-rate, while the ones that came off my disco *may* be dual or variable-rate - the wire diameter appears to taper towards one end of the spring.
half a days graft with the spring compressors and other stuff got 'em fitted. The front end sat nicely about an inch higher than standard, as planned. The rear, although it felt more taut and "springy" was about at standard height still. To cure this, I made up spacers for the rear axle, which give the desired 1" lift. These are in the form of a solid disc just under 110 mm diameter and 25ish mm thick. The top surface has been machined to mate with the bottom of the spring cup, which has a hole in the middle. Somewhat to my surprise, there's no corresponding shape on the axle for the cup to locate on (once you remove all the rust and crap) so the bottom surface of the spacer is simply flat. the 2 bolts which hold the spring and cup down were changed for longer ones which now go through the spacer as well.
So. was it all worth it? well, I reckon so. The vehicle sits nicely level and about an inch higher than standard, as I wanted, and feels a lot more positive on the road. This one has a front ARB, which does a better job of controlling roll than the rear one which is fitted to the other disco, but it was still soft and rolly on the road. The steering is a tad lighter, probably due to having marginally less castor angle due to the suspension design - the more you lift the suspension, the less castor angle you get - I've seen "corrected" swivels for sale for things with more extreme lift, but I don't think for a 1" lift that they're necessary.
Downsides? It's lost about an inch of suspension travel (which could be regained by fitting different turrets/rear damper mounts or longer dampers), but for almost all the use I put the vehicle to that's irrelevant. The only other thing is the lightness of the steering, but it's not so light as to be uncontrollable and you get used to it.