Hi Bec, 180m of cable to supply a house with 50kWh/day will be quite expensive, and consume quite a bit of your budget.
Becisme wrote: Conservatively I can see us using around 50kwh daily.
An off-grid system to cover that sort of energy usage will need to be huge
Based on the calculators I've used we would need at least a 7kw solar system with a 12kwh battery,
That would be nowhere big enough in PV or battery for 50kWh/day for an off-grid system.
Average annual global solar radiation, eqyuivalent to peak sun hours, in Canberra is 4.83kWh/m^/day, which is only a couple of percent less than I get here, so a comparison with what I have may be useful. I managed a couple of years with no generator use, 21kWh of Lithium battery storage and 3-4kW of PV. However, when required, I could cut my use down to about 6-8kWh/day, with only 2 people in the house most of the time. In sunny summer weather I could use well over 30kWh/day.
In more recent times I have much greater energy use, minimum of over 15kWh/day, and even with 7.7kW of PV, I need to use the generator at times.
If you could cut usage to under 30kWh per day during periods of cloudy weather, you might get by with 15kW of PV and 50kWh of LiFePO4 battery, and some generator usage.
It will cost significantly more than your budget though.
I think just going with a smaller system for now and expanding later on when the budget allows would be a good idea. Grid connected with battery storage may well end up being the best way to go in your case.
Have you obtained a quote to get the power run to your house site?