I’m as confused as hell!!

I had WiFi issues so I have just added TP_Link Deco P9 mesh network. I have 2 PCs hard wired to my Virgin Hub 3.0 Broadband router and sonos works fine. I changed all the Wifi devices including mobile phones to the NEW Wifi network name and password. 

Now the SONOS android app only picks up ONE of my 11 Sonos speakers. 

I tried everything. I even tried to revert to my old network name and password but I only got one option to do this. THis is offered only when no network is detected ? I cannot find anything in the android app to change the network or password?

The confusion is that I now have 2 networks…. A wired one and a wireless network covering the entire property. I use the wired network 90% of the time while my family use the Wifi Only. 

Please HELP!!