Looks to be like lots of compression artifacts too. I think we're coming to the conclusion that the replacement camera itself is ok now, and the remaining problems are to do with the limitations of 1080P and how the software processes the video.
I did notice that the original camera managed to make the very close plastic surround at the bottom of the rear window quite sharp (you can see a little of its 'grain'), whereas the replacement shows it smoother/more blurry suggesting the focus is now optimised for further distances, as it should be.