Seagate's SeaTools for Windows gave a FAIL error when fully tested "fix all long".
I managed to solve the HDD issue by fully deleting the partition (using a Windows PC), making a new Simple volume and formatting NTFS default (which it was previously). I also completed a slow complete NTFS format (which takes many hours to complete on a 4Tb drive compared to Quick Format) to ensure the sectors were all ok.
It is possible that Seagate used their "MBR workaround" format on these large external disks as I have found before with 3Tb external drives.
It was done gets around the 2Tb limitations of a lot of old hardware that cannot read relatively GPT partitioned drives.
This includes old PC and TV's with built-in crap media software.
At least the HiMedia can now log and read the drive. All good
