Cheers for the feedback. Yep thats what it looks like all the displacements are weird whatever settings I try.
This shot has had a hurdle at literally every step.
The reason for the huge shift is the src OBJs are enormous and are resized to .01. I made a conscious decision not to run them all through modo and bake in the size to save time.
The result is with the instance cache bug the model then fills the screen when rendered so thats why the huge shift. The scene is 8k at its widest so thats the number I chose. Im gonna try and reduce it now I know about this issue with displacements far from the origin. Thanks for the suggestions. If I have to I will go back bake in the size change and then do like you suggest. Stick a house on top of the offending objects.
This population cache thing really needs fixing.
Cheers.
James.