Hi CoopGav,
Welcome to Apple Support Communities. We understand that you're having an issue with adding your Opal card to your Apple Wallet. We'd like to help.
We see that you've already confirmed some of the requirements of using a specific card with the Apple Wallet. It's possible that you'll need to reach out to Opal directly since they would be the best ones to confirm if adding their card is possible or not. Then, check out these other steps to make sure that things are set correctly and expected to work on your device: If you can't add a card to Apple Wallet to use with Apple Pay - Apple Support
Learn what steps to take if you can't add a card to the Wallet app to use with Apple Pay.
1. Check that you're able to use Apple Pay:
* Contact your card issuer to see if they support Apple Pay.
* Update to the latest version of iOS or iPadOS, watchOS, or macOS.
* Make sure that you are in a supported country or region.
* Check that your device is compatible with Apple Pay.
2. Check for services outages or connection issues.
3. If you see the message "Could Not Add Card" or "Invalid Card," contact your bank or card issuer.
Apple does not approve or decline cards for use with Apple Pay. If your card was declined, contact your bank or card issuer.
If you continue to have issues after following these steps and speaking with Opal, let us know exactly what happens when you try to add the card and we'll continue to help from there.
Take care!