Body lift

Hi all. I'm looking to be doing a 3" body lift on my discovery 300tdi any advice on what modifications I may need to do once lifted

3" is quite a lot so as well as long springs (or air bag spacers) and long shocks, you will also need extended brake lines and maybe extended ABS sensor lines. If air suspension you may need to think about height sensors, not sure if it affects ACE.
You will also want to check your prop shafts carefully for rubbing and you may need different mounts to cope with the increased angle. If you are putting on really big wheels and spacers, and why would you be lifting 3" if you were not, then you may need to extend the steering stops and the bump stops, trim the bodywork and add some arch extenders. Obviously you will also want tree sliders, and HD bumpers front and rear to improve the approach, departure and breakover angles. All this will put a lot of strain on the hubs and steering components, so be ready with the spanners for when they need replacing early. It will handle like a pig on the road and you will want to keep the speed down on the bendy bits. If this is for extreme off road playing fine, but if this is overland prep then think very carefully about what weight you want on the roof. A hard top roof tent, an awning, a hi lift jack, a shovel and some jerry cans of fuel would make it really top heavy and uncomfortable to drive.
Have you considered a 2" lift? If so, lift kit plus brake line extensions and you are done.

I've not done this to mine you understand, I just did a search.

I've already done all that it's on a +2" suspension lift and a +2" body lift. With extended brake hoses and arch extensions. It's on 33 12.50 15 tyres with 50mm spacers. I was looking at the idea of going up a inch on the body from 2 to 3" was just wanting to know if anyone has done it and what will be needed to lift it. I think I might need to extend the steering column possibly fit a defender one as they are a bit longer I think.
Many thanks

Sorry I didn't notice that you were talking about a body lift. If you have already lifted it a total of 4", that must be a serious off road monster! We need pictures.

Personally lifting them sky high just makes for a less stable vehicle on and off road. You can fit 33” tyres to a stock suspension Disco if you trim the arches.

Most spring lift kits just reduce the amount of downward suspension travel too. If you are building a mud truck and moving to the eastern USA go for it.

Body lifts. Not done one on a Disco but you may need to look at gear linkages. Fuel line to the filter. Steering column and hoses on the rad. Plus they usually end up looking odd at the front.