To answer my own question, this was in the cleansing prospectus dated 3/6/19, https://www.asx.com.au/asxpdf/20190604/pdf/445l71wzz1n07x.pdf:
Total Shares 821,008,607
Existing Options (unquoted)19,285,715
Existing Options (quoted) 33,223,543
Fully diluted share capital 873,517,865
As far as I can tell, that wast he last public document that disclosed the shares on issue.