There are many rust prevention products in the Australian market, aimed at cars used on a beaches or harsh mining environments. I have not used one myself, but here are a few samples:
- ERPS, how it works here;
- NILRUST;
- Endrust (spray on);
- CAT systems and many more.
That said, the most modern cars have decent rust prevention built in. Such extra protection is probably only warranted in harsh environments.
I am considering 1 and 4 for the INEOS, as my Grenadier will live a hard life traveling Outback Australia.