Thankyou for everyone who has offered feedback.. I have had my headunit diagnosed from an auto electrician and it appears the headunit has just failed without any electrical wiring failure.
For those that have the same issue as I have, your headunit is under constant power from the battery with the only fuse sitting in the boot in the black box near the battery and another in the side of the headunit where the wiring harness sits. There is no wiring running to the ignition switch as the headunit uses wiring running to the body control unit to recognise when the ignition is switched on.
So if your headunit dies you need to check power running to the wiring harness if it is showing 12volt then the wiring is good and the issue sits within the headunit itself.
This is what I am being told from the auto electrician.