I'd be tipping that there would be a constitution. Private companies can use the replaceable rules from the Corporation Act, but any changes to that need to be documented in a constitution. Good luck getting a hold of that,
There is some really great information on the Wests Magpies website about how the boards of Wests Tigers Pty Ltd, Magpies FC and Wests Ashfield League's Club are constituted. You can read about it here:
https://www.westsmagpies.com.au/the-club/teams-boards-ownership/
But what it boils down to is that there are 20 debenture holders for Wests Ashfield Leagues group (now called Holman Barnes Group) that effectively control everything.
For the HBG board, there are 7 positions, 5 of which are appointed by and from the 20 debenture holders. 2 positions can be directly elected by members of HBG. Those members are people who have had Wests Ashfield Leagues Club or HBG membership for 3 years or more.
For the Magpies FC board, there are 7 positions, 4 which are appointed by HBG board and 3 positions which can be directly elected by members of Magpies FC. Those members are people who have had Magpies FC membership for 3 years or more.
For the Wests Tigers board, there are 8 positions, 4 which are appointed by HBG, 1 director appointed by Magpies FC and Balmain Tigers RLFC respectively and 2 independent directors, who are appointed by the board of Wests Tigers Pty Ltd.
So by virtue of their majority on all 3 boards, the 20 Wests Ashfield Leagues group debenture holders are responsible for all the decisions made regarding Wests Tigers and due to the way the Wests Tigers board is constituted, there is no way to boot them off or otherwise hold them accountable. Also, a change to the way the board is constituted or appointed would require the consent of the current board, so there is no way to force that change either.
There's a great little opinion piece on the Wests Tigers Podcast website called "Democracy lost: Wests Tigers fans now have NO say" by Joel Helmes that really sums up the issue well. Definutely worth a read.
Personally, I think there are two ways for change to happen, one the NRL steps in and pressures the club into change or the debenture holders are convinced to do so without pressure from the NRL. Either option would require massive community support and at the moment, I just don't see that eventuating.
If you wanted to build that support, finding people like Joel and getting them onboard would be a good start.