[allanv6gt]

The picture above shows Mk3 Cortina , our TC / TD models.

And thanks to that fountain of all knowledge...Wikipedia....
The P100 is a car-based Pickup truck, initially introduced in South Africa in 1971, based initially upon the Ford Cortina Mk3........

The P100's bodywork changed for 1977, to correspond with the Ford Cortina Mk4.....

In 1988, the P100 was rebodied with a new Ford Sierra based cab and tray.........

So, P100 is a badge (like Escort, Cortina..) , rather than a particular model code (like the Anglia '105E').
Any in Australia would have to be a private import.