I do more miles than that each year just walking too and fro in my workshop looking for things/tools I just had a moment ago but cannot find now!
Seriously though, with that small mileage each year, provided you are using good quality oil, really the only oil that would be getting contaminated is the engine oil. Tranny and transfer case, diffs, the oil does not get contaminants unless you drive a lot through water and on dusty dirty roads, or tow heavy loads or overheat the auto trans, (which I suspect you do not), you could get away with only doing the engine oil and filter yearly, leave the other oils to changes on a normal mileage basis, whatever LR specifies, I'm not up on later Landies, maybe a only a level check each year for these.
You are just wasting money draining out good clean uncontaminated oil, not to mention wearing out the drain/filler plug threads.
Whilst I was still working heavy vehicle maintenance in mining we had gone over to oil sampling rather than the time/distance based changes, many modern lubricants have extremely long service life before the additives had depleted in the oil, the base oil or synthetics always maintains a high degree of integrity, just the additives "wear out", oils were regularly sampled/analyzed for remaining additives and contamination and only replaced if problems were found.
It had been found they were tossing out a still viable/valuable resource with wholas bolas oil changes, some of the dump truck engines held 200litres, not to mention the transmissions/drivelines, operating costs were reduced by significant amounts without detriment to the equipment.
But it comes down to each Landy owner doing things the way they are comfortable with, me, I like to run synthetic oils in everything, (even my old 300tdi D1), simply because personally I believe it's the best for the job, it has been proven to me that better oil gives better protection, but I am not going to start that old debate again.
