The tv is a LG 55UF770T which I think is 200hz.
I tried changing the xbox one s settings back to 50hz and and also 720p but no real differernce with picture jitter. Picture was generaly grainier at this setting as you would expect.
My bigger problem now is that the picture continually freezes whilst watching the live games. Have to keep reloading the stream up to 15 - 20 times during the match. Seems to work ok when watching replays the next day. Social media seems to indicate that there are lots of people experiencing this problem.