Thank you, the box is a couple of years old, but the software updated today without problem. All very strange... other apps (MY5, You Tube, Sky news live) on the ROKU are fine, all synchronised. Even other programmes from Discovery plus (Lifestyle, Houses etc) all fine and in sync. However anything on Discover Sports, live or on catch-up are out of synch... just watched live snooker and you can hear the ball being hit 10 seconds before you see it...madness!
Last nights GP is still out of sync, only option I think is to cancel Discovery sports stream and get Eurosport through Sky?
Technology eh!