Hi Tony,
Not sure, Tony. The bodywork and axle look like No.1 or 2 trailer (No.1 trailers were all converted to No.2 standard) but the canopy frame and canopy are much more extensive than the original No.2 canopy, which was made up of half circle hoops with a simple canvas cover, like a covered wagon. The canopy was designed to cover a single stretcher case, so was not very high. The trailer was designed with apertures in each end for the stretcher handles to protrude through.
I'm reasonably sure there are No.2 trailer (with and without canopy installed) images in this file:
https://recordsearch.naa.gov.au/Sear...=649070&isAv=N
Hopefully, someone will feel the need to have the file copied (which will automatically make it available on the website).
Mike