Thankfully I am in full control of the entire Moodle site so no permission limits on my usage - I have got the SCORM files working fine for Guests that are not logged in it was simple. The only complexity I face is the need for them guests to first go to a pre-screen and press enter. I have fudged this by including an information message to guests on this pre-screen to make it look as if I wanted the screen there. I am using Moodle 3.5.1+ (Build: 20180817)
It would be much cleaner with out - I have a workshop next week on Moodle and will bring this up to see if there are any other thoughts from others more skilled than me.