2. The GDC, the internet, and complaints that do not stop
The GDC
The GDC regulates professionals to protect the public. It does not re-do a filling or refund a private fee as a first-line customer-service desk. Do not send every unhappy patient there as your opening move. Do not block someone who has a genuine public-protection concern (for example dishonesty, sexual misconduct, or a pattern of harm).
Online reviews
A public reply must not reveal clinical detail or confirm that someone is a patient if that is not already obvious in a lawful way. “We are sorry you had a poor experience — please contact the practice so we can look into this” is safer than a point-by-point clinical defence on Google. Do not harvest the review into the clinical record as gossip; if it is a complaint, handle it through the procedure.
Persistent or abusive contact
You can still be polite and still set boundaries: one named contact, reasonable frequency, and you will not accept threats or discrimination toward staff. “Vexatious” is a high bar — it is not a label for someone who keeps asking because you have not answered the original points. Take advice from your lead and indemnity if you plan to restrict contact.