Yes, but you can get a wof afterwards if you're really bothered by its 'legality.' It's treated as one of those recommended laws. Even the police or rangers don't say anything. All they're concerned about over there is the self containment due to people shitting in bushes. As for not connecting to a 230V. We had a Waeco fridge that ran all the time at 3C, charged two phones, walkie talkies, two laptops, and a camera for maybe five plus hours a day, and NEVER had to plug in to anything. Why? Because we had a big enough solar panel and had changed everything to run off a 12V.
But your last bit I'm curious about. Go ahead and show me something like what you described that is around $6000. Regularly. We're not talking about one every blue moon.