How do I remove an old AppleTV from the Home app in iOS18?

I wiped my old Apple TV a few months ago and passed it on.

Yesterday I updated my iPhone to iOS18. Since then, the Home app keeps saying "The home hub is not responding". This didn't happen under iOS 17.

I looked online for this behaviour and found a discussion from 2020 here:

How do I remove an old AppleTV from the H… - Apple Community

I followed the suggestion of checking on what devices my Apple ID is logged on but the Apple TV is not in the results list.

I have a couple of iPhones, a Windows laptop and a TV (LG) which suppoorts mirrorring and the Apple TV streaming service. I have no other Apple devices.

Any ideas as to how I can tell Home that I don't have that Apple TV any more? All suggestions and observations gratefully received.

Thanks,

Chris