There is a trailer up for auction at Manheim Fowles Darwin tomorrow.
many people know them as Humber trailers, for use behind the Humber 1 Ton, but were also used behind the Inter Mk3, Mk4 etc. Given it's camo scheme possibly also used behind the Unimogs.
http://www.manheim.com.au/trucks-mac...defaultImage=0
Some were made by Corio Engineering in Victoria, most however had flat top guards.