I thought it was because of third party software running in the background and seemed to have narrowed it down to the Logitech mouse software.
Apparently not as I’ve had a couple more crashes.
A further search found a thread in the Apple Communities that gives an interesting possible explanation:
”It seems that the initial upgrade from Sierra to High Sierra 10.13 might lead to some corruption of the admin account from which the Mac was upgraded.”
And, while the errors seem to indicate a power management issue, corruption of the admin account can lead to wake/sleep errors.
The proposed solution is to create a new admin account, log in to it, delete the original account (leaving the home folder intact) and recreate it pointing back to the original home drive.
I also found a thread suggesting that changing the MacOS
hibernatemode from 3 to 25 (safe sleep to proper hibernate) could also help.
So, I have recreated my admin account and changed the hibernate mode. We’ll see if they help.