The Gorse Fox is cautiously optimistic. A full shutdown and reboot of the failed backup drive seems to have kicked it back into life. Diagnostics show everything to be ok, no alerts have been posted, and all of the files that he expected to be there, are there.
As the next set of timed backups commences the drive should be brought up-to-date with the changes that have taken place while it was not functioning. Equilibrium has been restored.
(Now if only GF could reboot his hamstring).