And just like that everything is not working well. It seems I’ve jinxed myself. Timer still works but no Home commands work. For example, if I speak into the watch saying to turn on the ceiling fan, open garage door or turn on the kitchen light etc, no joy. In fact, the Home app is missing from my watch. I can’t recall if the app was ever there, but commands always worked. Oh well, now I wait and see.
ETA - “switching listen for” back on fixed it, but now I must say “Siri” or “Hey Siri”, that wasn’t necessary before. It’s also quite slow, but maybe it’ll get better over time.