Thanks guys, I have had some sleep since posting, and I think I know what the problem is, I will try an idea when I get into work.
( the jitter is vertical, not horizontal which is rock solid )
I have got very good horizontal resolution, I can even repeat my 16 bit wide graphic more than 6 times across the screen and the edges are crystal clear !
and I am running at 1280p x 720 pixel resolution on the LCD screen.
I will post the idea when if its all working.