The only problem I can see is that you're lifting the spring by 2 inches with the spacer and lengthening the shock by 2 inches so, unless you intend using +2" shocks, you're loosing 2 inches of drop on the front axle. The same applies to the rear unless you're using a 2 inch drop plate for the top shocker mounting.
Looks very good but it'll "top out" the shock quite easy on the rough stuff leading to premature failure of the shocks.
I've always said that if you're lifting a vehicle like a Disco then you're much better off getting springs & shocks to match the lift you want. That way they are correctly rated for the lift and you don't loose any performance from the suspension as a result.
If you raise the suspension then you're also raising the CofG as well and the standard springs weren't designed to operated like this and you may find that the body roll is increased as a result of the using the spacers. If you've got anti roll bars fitted then this isn't such a problem but these will also require 2" spacers to stop them inverting when off road.
