If a PCN shows your registration at a place your car was not, someone may be using cloned plates: copies of your number on another vehicle of a similar make and colour.
Check the evidence first
Ask the council for the photos or video (for camera PCNs outside London you are entitled to stills or a viewing free of charge, SI 2022/576 reg 3(3)). Compare the make, model, colour, wheels, stickers and damage with your car. A misread plate (for example an 8 read as a B) can also happen.
The ground to use
Your vehicle did not commit the contravention, so the ground is that the contravention did not occur as alleged against your vehicle. Explain where your car was, with evidence: work records, receipts, photos with timestamps, dashcam, or a statement from someone who was with it.
Who to tell
Report suspected cloning to the police and tell the DVLA. A crime reference number strengthens your representations, and the council and any later notices will see the pattern.
More than one PCN?
Cloned plates often bring several PCNs from different places. Challenge each one within its own deadline, and mention the others.