Thanks #moodler - now complained on the feedback link. "Dear Apple Australia, why have you not released the Airpod Pro Hearing Aid/Test feature in Australia yet? Waiting months for TGA approval is bad enough, but they approved it on 18 December 2024. Why such a long delay from Apple? This is a critical feature for users like me who are hard of hearing. Thanks Robert"
Some time as passed since my post and I am now happily using the hearing aid feature, with or without a BlueTooth connection. The next cool feature will be with iOS 19, when they can "auto-translate" from the spoken language to EiE (English in your Ear). Thank you to those who posted the Apple Support article.