So. As seen in the picture there is a bump node used and the effect disappears after joining the eye to the body. (The eye on the left is joined, the eye on the right is not).
I've tried unwrapping the eye, baking and using an image texture before joining the objects. But as shown in the attached image it bakes black, this is with the diffuse bake type.
It just bakes the same or a different solid colour with different bake types. So I'm confused as to why this is all happening. Any ideas? Am I going wrong somewhere?