Is Copperas Road, Brightlingsea, CO7 0AR private property?

[saladdays]

The other evening I parked down Copperas Road, Brightlingsea, CO7 0AR. I then noticed this sign:
I then drove off as I'm not a weight-lifting, steroid-taking company director. Is it public or private? Are £85 PCNs dished out on Copperas Road? Thanks in advance.
I was parked where the red van is: https://www.google.co.uk/maps/@51.8057776,1.026147...

[Zeeky]

Could be both. Public right of way with private rights to park. Common with unadopted highways.