VH-UMG
VH-UMH
From the links above, the white highlight contrasts the registration so you are close I reckon.
UMH was up in Sydney By '33 and UMG was knocking around in '31 with the black rego on the white background but the next year the colour contrast had changed so between UMG & UMH it is possible the image was taken '31 or '32 or a bit of '33 depending when UMH went to Sydney.
I find it interesting so many people are crowding around that particular aircraft. It's like it was an important arrival. Far too many people for 10 pax.