In an ideal world I agree that the vehicle should be used, but in the real world….
I leave a LR D3 regulalry for up to 3 months and have worked out the following:-
1) Clean the vehicle - thoroughly inside and out;
2) Buy a good quality cover that allows a bit of air circulation but is secured against wind;
3) Pump the tyres up to the recommended pressures;
4) Check and top up all fluid levels - oil, coolant and windscreen wash fluid;
5) Fill the tank - otherwise you can get condensation buildup in the tank;
6) Plug it in: I use a CTEK trickle charger for the Disco main battery. For my van (not a Cali) I leave it hooked up and cycle between vehicle and leisure batteries. Not sure about the Cali on this front - others may be able to help on this score;
7) Peppermint oil around the vehicle - will keep spiders out!
8) Depending on your location a rat/mouse trap may be appropriate outside the vehicle - rodents can create havoc with wiring and like a shelter away from the elements;
9) Empty water and grey water tanks;
10) Take any food stores out - they will deteriorate (well maybe not the tinned stuff);
11) If you can take the vehicle out every 3 weeks for a good 1 hour run - run the air-conditioning and the heater, then put it back;
12) Use a suitable treatment on all rubber seals round doors and tailgates - this will stop them sticking / freezing to the paint work;
Thats it really - take it easy when you restart - the tyres will have flat spots (these come out after a few miles) and try and give it a good run on a motorway - this gets everything working with a minimum of stress on the vehicle.
I am not sure about the points raised by the other posters - I think there are more problems with diesel vehicles regularly used for short runs when the DPF can start to clog up and things like EGR valves start to stick as the engine never gets fully warmed up. I've been doing this with the LR for 5 years. Im not sure how you would tell whether a fault would have occurred anyway or was due to lack of use…
Hope this helps