These were not necessarily CMP or M/H based. I seem to recall that the AEC Matador that was used with the 3.7in AA gun had a "Number... (Aust)" version, but cannot recall what that number exactly was.
: It's not certain, either, that the numbered Aust GT's were wartime production, No 1 and No 2 were possibly prewar.
Similarly with the 1/4 ton trailers:
No 1 was pre-war and not actually called a No 1;
No 2 was a low sided flat tray for carrying stretchers or supplies;
No 3, 3a, and 4 were Aust designed copies of Bantam Jeep trailers;
No 5 was the Land Rover box trailer of the 60's ,still in service today;
which shared many components with the RAEME trailers, which were'nt given a number!