Ah, yeah,. that's where it was at.
The problem solved itself. I had alt-tabbed for a while, thinking of a way to solve this. And, well, the game crashed; lol. So I could pick up from my last save.
The travel-thing I had tried, couldn't target with spells. I've tried bombing/barrelmancy/health potion lobbing, but she was stuck *in* a rock face. Nothing could hit Tav.
And yes, she was down near that bit; but on the disc-side of things. Honour mode so I can't go back, but will look for a path down next time. Thanks.