Another possible partial solution... I stress POSSIBLE.
If you have enough battery (Say 3 pair of GC-2) then a BIG converter say 100 amp or more (3 pair can accept 200 amps without issue, or 210 if you want to know the upper safe limit of charge) and a good size (2000-3000 watt) inverter to power Microwave, TV's (Which won't work Down under either) and such might do the job.
Make sure the converter is "Dual voltage" and plug in,, Some switching converters (modern ones are often of this type) can take as little as 80 volts to as much as 300 without damage, and do not care about 50/60 HZ either (Check teh specs) they can make 12vdc (well 13.6) fast enough to feed the 2KW inverter (that would take about 200 amps max) and it can run all the stuff I have to run on 120.. Water heater on propane. Fridge on propane (in fact unplug it) and make sure the converter is plug in so you can Unplug from the RV and feed it independent (mine can do that) Turn off the water heater as well (Turn off.. well turn off ALL the breakers in the MAIN breaker panel, leave only the inverter Sub Panel on.)