Yep, finally got it sorted. No matter what I tried I couldn't get the menus for the receiver/amp to display on the TV screen. Fortunately they also display in the small digital display on the front of the receiver. I eventually found the A/V sync menu and had to set the sound delay to 140ms to get it in sync.
One school of thought is that it may be related to the new TV's 4K upscaling capabilities.
Thanks to everyone who took the time to answer.
Jim.