well, not sure how it got in such a state, but following one of the filed bugs I found, I added an entry in /var/lib/bluetooth/../linkkeys that was basically a copy of the previous line but with the BT address of the keyboard.
Then it showed up as a paired device, but as is normal for me, it would not connect. I then deleted it, and re-paried and everything worked fine. And I'm now typing on my bt keyboard again.

Werid problem, but all ok now.