Yes the TOGO PCB was replaced as well.Tried a factory reset - still the same.
Checked the exif data - no serial number (listed correctly on a previous picture) which may leave me in a quandary with Nikon for any future repairs. I'll ring them tomorrow.
Also checking the finetune with Focal software, Focal doesn't recognise any adjustments (ie setting the range) to the camera. Looks like no data flowing between the two.