Hi,
As an update, the PCN has been cancelled by Community Health Partnerships.
As mentioned in my initial post, I had contacted feedback@communityhealthpartnerships.co.uk (as suggested by PALS), and they agreed to cancel the PCN "as a gesture of good will" as it was due to an "honest mistake" (quotations are their words), I had proven we had a hospital appointment at the time of the incident.
They also warned they will not intervene for any future PCNs.
Hope this is useful to others who have similar experiences.
Thanks,
Daniel.