A wired Sonos speaker or Sonos Boost (both make a Sonosnet, that gets the Sonos system off your wifi) should always be connected to the first node of a mesh system, which in your case seems to be the BT Router. The Move (and the Roam) however do not connect to Sonosnet because their mobility will degrade the Sonosnet. So they have to be connected to your wifi.

Thank you. That is clear about the Move. I assume the first node of the Mesh must be the BT Home Hub as the disc only has one ethernet port which must be connected to the Home Hub. Sonosnet doesn't appear as a WiFi network but then maybe it shouldn't!

No, Sonosnet is a hidden WifI network, so you will not see it as a standard WiFi Network on a phone, laptop etc.

The Mesh of Sonosnet and Mesh of BT Home is a different Mesh system, as long as they are all on the same network, you should be fine…. they need to be able to communicate with each other.

Plugging into the home hub, should be fine, as long as the BT Home Mesh does not set up a new network of its own.

Are  you seeing any issues?

I used to use Sonosnet and Google WiFi mesh, but I moved over to WiFi connections for the Sonos devices and they all connect to the Mesh WiFi directly.

Direct connection via WiFi seems to be the recommended connectivity these days, seems they moved away from Sonosnet being the default and recommend method. Sonosnet seems to be recommended for certain scenarios and fixing certain set ups.

Seems to be rock solid since the move to WiFi only.