Got it

The Gorse Fox is delighted to report that, on checking all of the overnight backups, the fix that he developed yesterday has solved the problem of the hibernating disks. No, as each backup job wakes up it runs a small script to go and look at the disk and then waits for 10 seconds to make sure it has "spun up". Then the backup kicks in as usual.

Now he can return to other matters such as the "tawnyowl' rebuild and what to do, longer term, about media storage and streaming.