http://www.ebay.com/itm/271880949367
This jacket was made in 1958 by the Commonwealth Government Clothing Factory in Bank Street, South Melbourne, Australia for the Australian army. It is marked a size 13 in their military sizing. Please refer to to the measurements for a good fit.

Chest (pit to pit): 23″ (doubled = 46″)
Waist: 17″ (doubled = 34″)
Shoulder to shoulder:19-1/2″
Sleeve (shoulder to cuff): 24-1/2″
Length (base of collar to hem): 22″