The right hand column confirms that the authorities had it listed as a 1942 WM20 with 54" wheelbase and 3.25x19 tyres.
The red annotations show that the machine above was disposed of via the large motorcycle dealer Hazell & Moore, and the machine below went to ALFSEA (Allied Land Forces South East Asia) presumably after 1944. Unfortunately nothing for 72312.
This is another one that is a close cousin with the Australian number on the tank - only 26 different in frame number.
This photo was taken in the Northern Territory and is the only period photo I have seen with what looks like it may have an Australian Bryant air filter fitted.