Update. Nothing caught in any traps except a couple of mice. I think these Rats were passing through to greener pastures and have moved on, for now? They will be back, so i've switched the attention to "Deterance".
For under $20, i bought a litre each of Citronella oil, Vinegar (double strength), Ammonia, and a spray bottle. To be used to clean up the mess they made, but also after going through Google found these were the most commonly used items as a Deterant. Grabbed some Moth balls too.
Leaving the bonnet up when not driving the Dmax!!, helps as they like cover. Leaving the camp drawers in the back empty until i go camping should help as well. Leave all traps set and check often.
A resident Carpet snake would be the best deterant but they don't hang around long either, probably because of the dogs.
Cheers, Steve.