Advice on spring assistors

we have a 300TDi, which last year we took to Tunisia, the only problem we had was it kept landing on the bump stops, we have been told about inflatable spring assisitors which can be inserted into the springs, rather than changing them, has anyone used them? and how good were they.
we will only be using the vehicle once or twice a year fully laden, and trying to find the easiest and cheapest solution to the problem.
thanks

Look for Firestone 'Air-Ride' product, they do simple rubber assisters or air pump-up ones.

RIDE-RITE™ Air Helper Spring Information

I believe that they have a distribution outlet in the UK, we used to by them from a place in Brentford in the 1970's.

Peter

or here

Matt Savage Land Rover Parts Air Lift Helpers