If I remember rightly, Land Rover gutters are only designed to take a maximum load of 100 kilos. I strengthened mine as the roof rack weighs most of that.

András is making a good point about centres of gravity, but there is a big difference between stability on tarmac at 90kph and stability in dunes at 50kph. My Disco has 25% uprated springs. With a full length Eezi-Awn roof rack, Eezi-Awn roof tent, second spare wheel and an awning on top, going into bends above 70kph is pretty scary I can tell you. Things are fine off tarmac.

Without wishing to start up another TLC versus Land Rover debate, I think it’s fair to say that the TLC is a stronger vehicle than the Discovery. Although 600kg on top with another 1,000kg inside must be pushing the axle weight limits of any 4WD.

On a TDi Disco you are allowed an extra 150kg on the front axle and 600kg on the rear axle - but not both together. A V8 can take a bit more on the front axle as the engine is lighter. Having said that, I reckon a TDi can take 800kg without a major risk of structural damage to either the suspension or transmission. But go above 1,000kg and you’re pushing your luck.

Mark, your hand book should tell you the axle weight limits and the EU (or EEC) kerb weight of your Disco. The EU kerb weight is calculated using an empty vehicle plus a full tank of fuel plus a 75kg weight on the driver’s seat. You local municipal tip or any commercial recycling centre should have a weigh bridge. Stick everything on your Disco, fill the tank up with fuel and find out what it weighs. Then add 20kg for every 20 litre jerrycan of fuel and water that you are going to carry, plus your weight and that of any companions (though this can be a tad tricky with some females).

If you are too heavy, leave things behind - no matter how essential you think they are. It’s better than breaking your vehicle in the middle of the Sahara.