Like others have reported, our Google Nest Display and Lenovo Smart Clocks all play ABC Radio National Adelaide when asked to play Radio National even though we live in Melbourne. Our home address on the Google Home app is set to Brunswick, VIC so this shouldn't be the cause. We did get one of the smart clocks to play RN Melbourne once, I'm not sure how we did it, and I did notice that it was streamed via the Radio app rather than via Tuned In app which consistent goes to RN Adelaide.
Thank you for your patience. I am sorry to hear that your Google Nest Hub and Lenovo Smart Clocks are playing the incorrect radio station. I can understand how frustrating this issue is.
For now, could you please send in feedback through your Google Home app or device with the keywords "ABC Radio National Adelaide." It will allow our team to further look into this issue.