After testing with both Hard Disk Sentinel and Seagate Tools

The 3TB drive is well and truly kaputnik.  It failed the same way with both diagnostic tools. 














I have filled out all the requisite information, printed out a shipping label, packed the drive and power supply into the original packaging. All that is left to do is put it in a Aus Post shipping bag, and send it back to be replaced.  Turns out it's under warranty until Oct 2015.