Install
This is the repository archive. It installs, but the folder name will carry the branch suffix and updates will not flow.
Install straight from GitHub with WP-CLI:
wp plugin install https://github.com/iwitness-design/rcp-commbank/archive/refs/heads/master.zipCommbank
A custom payment gateway for Commbank
Setup
Once the plugin is installed and activated, go to the Restrict Settings page in the WordPress Admin (Restrict → Settings).
Select the Payments tab and add the Commbank Merchant ID and API Password. You can generate your API Password by following the instruction here. Also enable Commbank at the top of the page and update the currency to "Australian Dollars".

Testing
Navigate to the Registration Page and create a new user. When the form is submitted, the payment data will be submitted to Commbank. Any errors will be displayed on the registration form. If there were no errors, then the member will become active and be redirected to the welcome page.