by mlines » 09 May 2016, 17:04
I think you are mixing up kerb weight, the caravan clubs recommendation of 85% of Kerb weight and train weight.
Your Disco will have a "Gross Train Weight" - GTW rating.
The maximum train weight for your Disco is 3500 + 3500 = 7000kg, this is the weight at which the brakes on the disco have been tested and approved and this is the level the law tests to within the further constriction that the 3500kg MAM for the trailer is not exceeded.
Now whether it is sensible to tow to this level is a different question. The kerb weight of my Range Rover is 2480kgs, the boat+trailer is around 2900kgs giving a GTW of 5,300kgs. At this level you know you are towing the boat as braking and lane changing etc have to be more considered etc.
The caravan club is more car focussed and recommends 85% to its members, but its only a recommendation