This is from the handbook page 95
• If it is necessary to increase the nose weight up to a maximum of 175 kg (385 lb), the vehicle's load should be reduced accordingly. This is to make sure that the GVW and maximum rear axle load are not exceeded.
So there is a good "margin" given most alko couplings in the UK are rated at 100kg from memory the DS as expected should not be the limiting factor.
Old ish post but thought i would jump in for some advice.
I'm going to use our Discovery Sport for the first time towing the bailey senator indiana series 6 caravan to Newquay and was looking for some advice on nose weight and tyre pressures. Looks like 100kg for the nose weight but unsure on the tyre pressure for rear and front typres.