@olliemann1 

„In the background“ means also playing on the Sonos soundbar together from both sources? Or is one of them playing from the tvs internal speakers? I suggest to check tv audio settings for output of the different sources and to restart the tv by unplug and replug to power. 
Ultima ratio would be a factory reset of the tv. 

Hi @olliemann1 

Welcome to the Sonos Community!

You mention having an Arc that might be a Playbar, but then go on to describe it as a Beam. These are three completely different products that connect to your TV in importantly different ways. Ordinarily, I would just check your account for clarification, but you don’t have any devices registered to the account you are using here on the community, so this is not possible.

Given your description of the issue, however, I can only come to two possible conclusions:

1. Something is wrong with your TV - please unplug it from power for at least 2 minutes (this restarts the TV's software in a way that standby does not achieve).
2. Or, much more likely, whichever soundbar you have is connected via optical cable to your Sky box rather than to the TV, in which case what you describe is expected behaviour. Please connect your soundbar to the TV’s optical output (and enable the socket in the TV’s settings) instead.

If you need further assistance, I recommend you get in touch with our technical support team who have tools at their disposal that will allow them to give you advice specific to your Sonos system and what it reports.

I hope this helps.