Adjusting the surround levels to “zero” or -15 doesn’t completely mute the speakers. So disabling the surrounds would be the best option.

Thanks , so it won't make any difference if I toggle them off and leave them flashing green ? 

As long as the flashing green light doesn’t bother you, then toggling the surrounds off won’t hurt anything.

Brilliant , thank you once again ! 

I’ll admit to having put pieces of black tape on the top of those speaker lights, as it annoys me when I have them “muted” that they blink. :)

Yeah tbh  not that bothered at the moment but when they're muted they should go a solid colour rather than blink .

It’s all personal, for sure.

I’m of the opinion that if I have the LEDs turned off in the controller, they shouldn’t light up when muted….but I suspect it probably often helps the CS folks because it doesn’t work that way. :)

If black tape is too much try some dimming dots, can’t find the multi-level pack I got as a gift but single level and color ones are available.

https://www.amazon.com/LightDims-Original-Strength-Electronics-Appliances/dp/B01BZBBITE/ref=sr_1_18

Thanks for all your replies , after I toggled the surrounds " off " the two LEDs flashed green which according to this 

https://support.sonos.com/s/article/226?language=en_US

It means they're ready for set up but they we're already set up and playing , I just toggled them off !! 

Just curious. Why buy expensive speakers and then mute them?

We dealt with all that here: