https://wolverhampton.moderngov.co.uk/documents/s241418/Public%20Spaces%20Protection%20Order%202023%20-%20Dog%20Control.pdfThe relevant section
4.6 As part of the consultation exercise into renewal and variation of the PSPO, consultation
was undertaken regarding a new requirement for a person in charge of a dog on public
land to be able to produce on the request of an authorised officer suitable and unused
means of removing dog faeces from the ground. Anyone who fails to comply with this
requirement shall be guilty of an offence if they are unable to produce suitable and
unused means of removing dog faeces from the ground when asked to do so by an
authorised officer. The receptacle / bags must be disposable, and this requirement is
unaffected by whether the dog has recently defecated. Exceptions to this proposal are:
i That person has a reasonable excuse for failing to do so; or
ii The owner/occupier or other person or authority having control of the land has
consented (generally or specifically) to that person failing to do so.
I would have thought that, "my car is 10 yards away and I have one or more there" is a perfectly valid response. It doesn't say it has to be produced from anywhere in particular.