Does that fact that the OP left before the NtD could be given hold any water? Have ECP used the 'wrong' NtK?
The Dropbox link doesn't appear to be working, so we'll need to see the NtK to check. Driving away from an attendant issuing a notice is not a magic bullet, but it
does mean one wasn't served on the driver. They'd therefore need to go straight to a Notice to Keeper that's compliant with paragraph 9 of PoFA.
A more straightforward line of argument, which can be used alongside any PoFA argument, is that the bay was being used correctly by two parents with a toddler. That one parent remained in the vehicle wouldn't appear to alter that fact.
