We can only await their response.
My reference was to this in your earlier draft:
'...as the CEO had he observed would have noticed and made note of had they followed procedure and enforce the TMO properly.' To the point of issuing the PCN they had enforced the restriction i.e. car without permit AND no exempted activity seen to be taking place. A driver does NOT have 20 minutes free parking, they may engage in the exempted activity for no more than 20 minutes provided it's continuous.
The issue of the driver speaking to the CEO is important. If, as you say, loading was a continuous process, albeit involving tooing and froing, then when alerted by the driver they should have checked in the car to verify this new info. They couldn't cancel the PCN but could make a note to this effect.
But they didn't. Perhaps through ignorance i.e. not considering that loading would make any difference anyway?