Which TV model? Which Sonos device? How are they connected?

TX-50DX750, UB900, Sonos Beam.

UB900 connected to TV HDMI1 by HDMI cable.

TV connected to Beam using HDMI1 Arc socket. Sonos Ones used as rear surround sound speakers.

When using bitstream options 5.0 is enabled bit there is a significant lip sync delay.

When using PCM settings there is synchronisation but I believe I am only getting stereo output.

What am I doing wrong and what should the settings be?

Check with Panasonic to see if the TV has any firmware updates. If not, you might have to switch to optical from the TV, if there are no HDMI-fixes available from Panasonic.

You are not doing anything wrong, other than assuming TV manufacturers adequately test all of their features.

You are correct on PCM - it is stereo, but it is simple enough that Panasonic don’t mess it up with a delay.

Thanks. I have submitted my query to Panasonic and I await their reply.

In the meantime I tried to connect the UB900 direct to the Beam by HDMI cable but this didn't work (as I suppose it shouldn't).

I'll try optical from TV to Beam as a last resort as you suggested. 

It looks like my Panasonic TV causes the delay on audio from UB900 to the Beam. The TV passes through DD5.1 but there appears to be a processing delay (which Panasonic support has been of no help at all).

I have taken an HDMI lead from Audio Out on the UB900 straight to the Beam but get no sound in spite of adjusting the audio settings. Perhaps someone can help me out on that one.

So I am stuck with PCM stereo on my 5.0 Sonos system when playing discs along with a lot of people out there (irrespective of make and model of TV).

Fortunately there is no audio delay when playing live TV or streaming.