Discovery 2 rear suspension

I need a bit of advice on what to do with the rear suspension on my Disco 2.

Its on std springs and shocks and it sits very low when loaded or towing. We to a caravan and a cattle trailer with it, also its frequently loaded with a large tool chest and tools.

Having looked on here, it seems that we need some bearmach hd springs, but I'm also wondering if a lift would be suitable as well? Not really wanting to go for a 40mm lift, but see that you can get 20mm lift and was thing of that. If I went for a lift would I need to change the shocks as well as the springs?

Thanks in advance

if you look at the spring rates you will see that lifted springs have a similair rating to std springs so they will not give you any advantage with load carrying, best go for the heavy duty springs as they have been designed for just what you are looking for.