Hi Dwaine Amos. I'm a Unity developer too, but I've never done anything with Watson Assistant using Unity.You should use the Service URL found at the IBM Cloud website on the page when you first open the specific Assistant as shown here:
The URL found on the "Assistant settings" page under "API details" is not correct (for this Unity project) although it is labeled "Assistant URL":
My project is not really an Avatar bot. I'm developing a game that checks the player's emotions and thus makes the game harder or easier. But it's going well.
If you have any doubts about the configuration, just let me know.