Mustrum - your tip was a good one, albeit very painful to get working still. I had a Sonos Play 3, and two Symonfisk Sonos Lamps to put on to an S2 Sonos controller. The main problem is that the controller and the Sonos speakers need to be on the same network, and indeed that does need to be 2.4Ghz seemingly for it to connect.
You start by switching all the speakers off and come out of the Sonos App on your phone/tablet. You go into the EE Smart Hub Settings Page and you Edit Settings and turn off 5Ghz. Then save and reboot the router.
You then go into the Sonos App and turn on your first speaker - in my case a Play 3. As it happened, I had connected that via Ethernet previously, and so it appeared on the new Sonos network I had set up. That perhaps speeded things up. After that, you need to Amend/Add the Play 3 product on the new network using the "Fix It" message which should have appeared on the App. It is about a 4 or 5 step process then and you finally get to connect to the same EE network as your App is running on.
If you run into issues, and this definitely solves it, turn off the speaker, reboot the router, turn the speaker back on and start the App again. The router reboot seems to clear out the issues.
Annoyingly, every time you then add another product, you have to reboot the router. It simply doesn't like adding a new product without that. It worked for each of the lamps each time I rebooted.
Thus, after about an hour, the three products were working. I grouped them and that all worked too. I then switched 5Ghz back on, kept my fingers crossed, and sure enough the grouped products all worked.
I remain convinced another problem is coming, and definitely one when I try and set up the S1 network for the older Sonos kit, but so far so good - big thanks to Mustrum 🙂
