Here is what the factory owner's manual for a Discovery 1 says about this:
TOWING FOR RECOVERY
If your vehicle is to be recovered by towing, the best method is via a flatbed tow truck. However, if it is necessary for the vehicle to be towed with all four wheels on the ground, always adhere to the following procedure:
1. With the parking brake applied, set the main gearbox and transfer box in neutral. Select 'P'- Park for automatic gearbox vehicles.
2. Ensure the differential lock is in the unlocked position.
3. Turn the starter switch to the first position to unlock the steering, and then to position 'II' if it will be necessary to operate the brake lights and direction indicators, and leave in this position while the vehicle is being towed.
4. Secure the towing attachment to the front towing eye of the distressed vehicle.
5. Release the parking brake.
NOTE: If, due to an accident or electrical fault, it is not considered safe to turn the starter switch, the battery should first be disconnected. If the vehicle has a discharged battery, the shift interlock will be disabled. The use of a substitute battery will enable the shift lever to be moved into neutral.
WARNING
DO NOT remove the key or turn the starter switch to position '0' while the vehicle is in motion; the starter switch must be at position 'I' to unlock the steering.
Without the engine running, the brake servo and power steering pump cannot provide assistance; greater effort will therefore be required to operate the brake pedal and turn the steering wheel. Longer stopping distances will also be experienced.
Long distance towing
Your vehicle can be towed behind a motorhome or other recreational vehicle. Follow the procedure for towing the vehicle on four wheels.
I myself would go to the extra trouble of unhooking the driveshafts for longer distances.
David