05-21-2019 11:55 AM
No worries. After I had gone through the motions with Lenovo, organising a warranty return - similar to yours it mysteriously re-appeared in Device Manager (after being greyed out for several reboot and power cycles) and started working again. Truly odd.
The only thing I can think of is that W10 must have been doing something, in some hardware abstraction layer, somewhere in the background. I had previously updated all the Lenovo W10 system drivers and even BIOS, to no avail.
There is now one remaining W10 update (2019-04 I think) that stubbornly refuses to apply, but otherwise it all appears to be working...for now anyway!
Thanks again for your help and interest.