My other wifi connected speaker (Play:3) is fine over the wifi. If I connect the Play:1 via wired ethernet it works (but nothing else appears...weird).
Can anyone help?
Best answer by Stoic Facade
Taking a look at the diagnostic reports submitted from your system we can see that your Play:1 has different wireless information loaded into it compared to your other two players. The Play:1 looks to be trying to connect to a WiFi network being broadcast by a wireless extender.
If your Kitchen Connect is permanently wired to your router the best step would be to factory reset that Play:1 to clear out the conflicting wireless information and then re-add it the system. The steps to factory reset the Play:1 can be located here: https://support.sonos.com/s/article/1096. Once reset try adding the Play:1 back to your system.
Provided that works as expected you'll also want to remove the WiFi information from your other two units as it is not needed. You can find those steps here: https://support.sonos.com/s/article/3488
I don't why a network conflict arose, given that I haven't chnaged anything in recent months. But I ditched the wifi setup since I am using my Connect in a Boost setup. Factory reset on the Play:1 and all is well. The case is closed.