I've just got to the crossroads quest and chose one and I was told to go talk to hunt outside a tavern but when I do it says I need specific knowledge to talk to him and I'm quite stuck on what to do, I've looked online but can't find anything, this is the only thing I can think to do and I'm not sure if this is the right place anyway?

Uh this is probably late but you need to go talk to someone else first. I think it's the lady who owns the tavern on the 2nd floor balcony. Some characters won't talk to until you talk to someone else who is usually nearby. The game automatically sets a waypoint for you.

Who's knowledge do I need to talk to grace Lauren?

No one. Talk to her first and then you can talk to Hunt.