Your black plug wiring has been modified for Aussie use - they do not come like that. 07MY RRS TDV6
Arctic Frost
Aspen Interior

Hi Gary,
I agree, I was about to post the same comment!
Regards
Barry 2017 Range Rover Sport TDV6 L494 SE Fuji White
2011 Range Rover Sport SDV6 L320 SE Fuji White Loved but GONE
2010 TRAKKA Motorhome Fiat Ducato GONE (What a dud, don't buy one)
2006 Discovery 3 SE TDV6 Automatic Chawton White/Ebony. Loved but GONE
2006 BMW X5 diesel White/Charcoal, Bought new, Gone after 12 years! Was Excellent.
Ex Member Range Rover Club NSW

Okay Guys,
It must have been done by the previous owner.
Just as aside, I do have a Jayco van which has its own inbuilt 240v to 12v Convertor/Charger/Aux. box and Battery.
There can be a fair amount of voltage drop via the 'normal' wiring. There are 'boosters' you can get to up the power to the Van, or use the Anderson plug method of a heavier wire from the Battery. Both of these put some extra work on your Alternator and some upgrade their Alternator to cope. Also it is advisable to have a cutout installed in the system so it protects the car battery voltage from dropping below enough to start the car i.e. Voltage Sensitive Relay.

I have gone down a different route and recently added a 80w solar panel to charge the van battery. The RRS is also wired up to accept a 4w solar panel to keep its battery topped up. They both have controllers to stop overcharging/drainage.
I have seen lots of vans with all sorts of Solar Panels but it was interesting to see lots of Tow vehicles as you got further north in Qld. with Solar Panels to run Waeco type fridges in the back and or assist with the electrics.