Audio Playing Once and supporting highlights.

I have a menu page that takes the learners off onto various scenes.
I want a first time through commentary so I used the approach recommended in the forums. (https://community.articulate.com/discussions/articulate-storyline/how-to-trigger-audio-only-once#)

the main difference between my example and the one in the solution I've borrowed is that in his case it's a short narration so he sets his 'turn-it-off' variable when the audio completes. My nararion is long and I think there is a good chance that people will click on one of the buttons to start the learning before the audio file ends. so what I've done it put that trigger on the timeline start for something else.

As the narration covers each area I throw a highlight box around this. (the trigger I mentioned is on the first of those)

I've tried a bunch of things to try and get the highlights to only show first time but don't seem to be getting anywhere with that.

I've tried all sorts of combinations of 'when revisiting' choices and if they suppress the highlights then don't suppress the audio.

Before I tear out all my hair can someone please help.

Thanks