I have tried:
Update all every frame is checked. Though there is only the camera moving in scene.
I had a camera plugin called Scoobycamtools (which has worked with octane in the past) I have removed this.
Applying keyframes directly to the camera
Applying keyframes to a Null parented to the camera
This is now a completely new scene from the one I was having the same problem with before.
Deleted all modelling cameras so there is only one. And that cam has a tag
The live viewer works fine, the problem is just in the picture viewer.

Any help greatly greatly appreciated!
Cheers
Poke!