I broken down on double yellow lines
Doesn't happen like this, there's a sequence of events which we need to know.
Being on DYL is, without further elaboration, a contravention. So, did you park there, under full motive power and control, and then find you couldn't get out of contravention because the battery was flat. And when did you discover this, before or after the PCN was issued? If before, where were you when the CEO appeared? If after, then you were in contravention and your subsequent discovery of a flat battery is not germane.
If you limped onto the DYL because you could not drive under full control and pulled over to stop at the earliest opportunity, no legal places being available? If so, where were you when the CEO arrived?
You need to flesh out the sequence.
Having said this, as you're going to tribunal anyway and procedural impropriety is an additional string to your bow anyway.