OP, the council are wrong, end of. Read your Highway Code - Traffic Signs.
Some while ago, Cp posted various tribunal decisions on the issue, but second-guessing still abounds!!
In your case IMO it does NOT matter whether an adjudicator accepts your account(that is escorting your 8-year old daughter into the leisure centre and returning immediately), the council are damned by these statements in the NOR:
'...I can confirm that area your vehicle wa(sic) parked in is classed as an on-street location..'
'You have stated that you were under the impression that the practice of assisted alighting is permitted. I can confirm that dropping off passengers for any length of time would not exempt you from the rules that are in force.'
IMO, just register your appeal.
Contravention did not occur;
Procedural impropriety.
You rely upon your formal representations and procedural matters arising from the Notice of Rejection of Representations.
You would add to your formal reps(called 'further representations') which you would submit later after seeing the council's case summary(you could do it now because the case summary is not primary evidence whereas the NoR is, however, I've no doubt that the council might embellish its stupidity in the CS, so wait and bring whatever other damning comments they might make to the adjudicator's attention).
If I were you, I would want this to go the full distance so that you can get the adjudicator's decision in writing on the fundamental issue of what you do on a regular basis being lawful. This should ensure that the council don't revert to their old ways but this wouldn't prevent them issuing PCNs because all a CEO would know is that there's an unattended vehicle on DYL, but at least you could prepare yourself with a standard challenge which includes the decision.
