FFS, this is bloody nonsense.
OP, are you still in time to request a review? If so, do so.
Interests of justice.
This whole issue has been clouded with who did what, where and when.
It's all irrelevant.
The only issue is: could you be considered the 'owner' and therefore liable in light of the evidence?
IMO, the answer is NO.
Would you pl just extract the evidence as it relates to Enterprise and you getting the PCN. Forget everything else. Put it in the form of a timeline.
which shows that:
Initial PCN to Enterprise;
Some waffly letter(apparently sent by Enterprise and addressed to you alone, so what's it doing in the council's evidence?);
Charge Certificate to Enterprise;
PCN to you.
There is no evidence that the council cancelled the PCN and the CC, just a PCN to you.
IMO, the adjudicator, who is the professional, should have spotted this and as a minimum adjourned with a direction to the authority to produce the evidence or preferably to have allowed the appeal on the grounds of procedural impropriety and that to delay would not have been an efficient use of the tribunal's resources.