Soundbar with bluetooth output?

The Sonos soundbars don’t have that facility, but I do know that all the current Bluesound products (including their Soundbar) have Bluetooth out at AptX quality. 
 

If it’s just for TV use then you can find a BT adapter that takes the TVs audio and transmits it to your headphones and would be much cheaper,

Thanks, do you have details of that adapter? Problem is, TV’s on the wall, and the back, where all the sockets are, is hard to access. 

Really depends on what sockets your TV has, you’re going to have to access them at some point. Have a look in the manual.

If your TV has an optical output then this might do the job…

https://www.amazon.co.uk/Avantree-Bluetooth-Transmitter-Receiver-Playtime/dp/B07JJCZ3WL/ref=asc_df_B07JJCZ3WL/?tag=googshopuk-21&linkCode=df0&hvadid=310847932305&hvpos=&hvnetw=g&hvrand=13083663260063991629&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9046557&hvtargid=pla-599902778385&psc=1

Thanks, thought I could avoid the problem by connecting to the soundbar instead…

Modern TVs can usually support Bluetooth directly. 

Though there have been reports of TV’s reverting sound back to Sonos soundbars from bluetooth.

True, but that could be addressed by disabling CEC or by simply powering off the soundbar.