Tom, following up on your response to Nigel's question #1. I exported a course from the Authoring Tool and tried to build it through CLI (command prompt) but got Fatal error: Unable to find local grunt. Following the web link below this error I worked out that you need to first run npm install in the command prompt before using any grunt command. This might be obvious to some but I'm new to node and grunt :)
Thought I'd post this here just in case any other newbies like me hit this error message also.