I have just set up 3 Deco M4 units connected to my Virgin hub (now as a modem rather than a router) 

My 2 SONOS 5 speakers no longer connect.

If I hardwire one SONOS 5 to the first Deco with an ethernet cable I can get it to work but I am unclear how I would connect the other. On line help is a bit uncertain about what can be done.

If I add a network switch to the first Deco does that mean I have more ports that act as if they were part of the main Deco and so will support 2 SONOS 5's?

i.e. If I add the switch and plug my Sonos speakers into two if these network switch ports will they work?

I ask before I purchase a switch and drill 15" holes through two walls to enable hard wiring of the SONOS 5's

Do I have other options? I thought having Deco mesh would solve my wifi issues but more have developed! [My previous Powerline extenders had failed after several years, and no amout of experimentation got them workingagain, so I didn't want to stay with that solution.] Deco M4 appeared much better until I tried to play music via SONOS.

Thanks for any support about this.