hi, maybe you could temporarily move your One speaker to the router and wire connect it to set it up -  you still may need a 2.4ghz enabled on your router

When you wired the Symfonisk did you select to Disable WiFi?

That setting actually disables the devices radio so it can’t communicate wirelessly with other Sonos devices.

If you did, then you can re-enable Wifi in the room settings.

@Derek15, 
All Virgin Media routers support both 2.4Ghz and 5Ghz WiFi and unfortunately the issue here is you did not need to reset any of your Sonos products - you should have simply followed the steps mentioned in this support link instead…

https://support.sonos.com/en-us/article/connect-sonos-to-a-new-router-or-wi-fi-network

It’s difficult to now understand from your post, precisely what steps you have taken up-to the present moment, but there’s a possibility that if you wired the ‘factory reset’ speaker, then you may have overwritten your original setup altogether. It’s difficult to know where the system stands at the moment, but I will suggest this… (note this may, or may not, work and depends on what steps you have taken already).

1. Power off the Sonos device that you have previously factory reset.
2. Cable a non-reset Sonos device to your router and power it on.
3. With your mobile connected to the new VM WiFi, reset the Sonos App in ‘Settings App preferences’ and on reopening connect that App back to the existing Sonos system (do not create a new Sonos system at any stage).
4. You should now see in the App the one wired speaker only and your original Sonos system.
5. Now add the new WiFi network to your Sonos system using the link I provided above and when that’s complete you can uncable your speaker to run on your new WiFi network.
6. Only when all that is complete and working correctly can you then power on your earlier reset speaker, but just factory reset it again and add it to your existing system from within the Sonos App using ‘Settings/System/Add Product’. Then all should continue to work fine.

Sadly, because it appears the wrong steps were initially taken with the new router switchover, it’s difficult to now know where you stand with your setup, but I hope the above general steps work for you.

Whatever you do, do not reset any further devices, as you may end up with more problems and having to start the Sonos system setup from scratch, as a new system and could lose all your services, playlists settings etc. My advice is to try to tread carefully.

Thanks for your help Ken I will follow your advice 

I knew I would lose the setting on the Speaker but as I don’t store Music or  playlists etc  on there is wasn’t a problem. I’ve got the new Virgin 5 hub so it’s set up just for 5Ghz  - I tried to split the WiFi into 2.4 and 5 but it did not work and I could not get anyone at Virgin other than the Bot! 
 

I have just followed the steps on the Sonos App to get connection and the last of those steps was to reset. 
 Thanks again 

I have the V5 Hub here too - it’s a combined 2.4Ghz and 5Ghz WiFi router where both bands have the same SSID & password - your Sonos devices should run fine on that router - Just set the 2.4Ghz band to use 802.11b/g/n/ax compatibility with a channel width of 20Mhz only and set the security mode to WPA2 AES/TKIP personal and you shouldn’t encounter any issues with it after that.