This is entirely caused by the TV. The Arc plays what it receives when it receives it. One solution is the HDFury Arcana, although that is expensive as it is designed to do more than cure lip sync issues.

Thanks. Would getting a LG CX tv solve the problem or do they have a delay problem? 
Before the Arc I had an amp and 5.1 speakers and never had this type of problem. Wanted the arc as it’s a cleaner solution but may have to go back to a

5.1 setup :/

I don’t know if a CX would have the same problem but it probably would.  But that is a drastic solution.

What is the position on getting Atmos from your Sky Q and XBox, with current TV?  

Purely experimentally, you might try using the optical out of the Sky Q or XBox (if they have one), plus the optical-to-HDMIARC adapter, to see what the sync position is when you bypass the TV for audio.

Hi all, 

as an update, I got an arcana which solved the problem.