Storyline Exit Activity under Moodle

Hi, I can see there are a number of older discussions about issues relating to the 'Exit course' trigger when running under Moodle in full screen mode, but I still can't solve my issue.

I am compiling for Moodle LMS and want to run the course in full screen mode. So I set the player to open the course in a new window and select "resize browser to fill screen". I include a "Complete course" trigger and an "Exit course" trigger on the final screen.

Everything works fine and, at the end of the course I return to the "scorm/player.php" screen which has an "Exit Activity" button top right. If I click this everything is fine. I can re-enter the course in Review mode and all is well.

BUT also on the "scorm/player.php" screen the learner sees the "Launch course" button and if this is pressed instead of the "Exit Activity" button the browser gives a "Error initializing communication with LMS" error.

Clearly, the "Exit Activity" does something that is required to be able to launch a new instance of the course.

I have tried editing scormdriver.js to change the "var EXIT_BEHAVIOUR =" settings to "ALWAYS_CLOSE" and "ALWAYS_CLOSE_TOP" but still get the same problem. I see that I can redirect the code to another html page - so tried setting:

var EXIT_BEHAVIOUR = REDIR_CONTENT_FRAME

var EXIT_TARGET = "lms/goodbye.html"

Sure enough I got redirected to the goodbye screen which told me I could now close the window - which I did BUT clicking the launch button still gives the error. So I'm convinced my problem isn't that the window opened to run the course in isn't closing. 

Does anyone know what the "Exit Activity" button does and how do I overcome my problem?