I don’t know what happened but there are 9,000 frames that are wrong!
For some reason between two keyframes, the camera swerves to the left over the course of 3000 frames for the centre, 45 and 90 degree passess. Very annoying.
I re-rendered and it still diverts, despite the keyframes being correct. I’ve had to recreate the keyframes from scratch and render. It looks good now.
41 hours of rendering and I have my replacement 9000 frames.
Total base rendering: 12 days, 1 hour.