My Type Cover came back to life today - after being unusable for many months.
* This proves the hardware had not failed.
* I had taken no particular action to fix the issue, I started as usual by turning on my Logitech kb & mouse. The type cover was already connected as I was using it to protect the screen.
* I did receive a notification balloon that the Type-Cover had been added.
* The only observations I have is that I installed all the available updates recently, and I also left it to discharge completely due to non-use for a couple of days.
So my assumption is that the fresh startup managed to allow the latest update to finalise some driver installation... For how long I don't yet know.