Having screwed-up the initial search, I then re-load and finally track the monster down to its cave.
You can see at the five minute mark that when I turn around, looking for Eskel, I don’t see him and realise I’ve run too far. Amateurish Witchering!
Monster Contracts are side quests in The Witcher 3 that you can take on for extra money and experience. You usually get Monster Contracts from notice boards.