ParkingEye replied the same day ....
"Thank you for your email.
In order for us to ensure that the information we provide is your personal data, we would require further identifiers and clarification of the data sought.
If this request pertains to a Parking Charge you have received, please advise of any reference numbers that apply, your full address at which it was issued and the relevant vehicle registration.
If your request solely pertains to vehicle data, we will require evidence of your continued status as registered keeper. Thus, we would require further identification documents.
Please provide the following:
• Your full name
• Your full current address shown on your log book (V5C)
• A copy of your log book (V5C) for proof of continued status as Registered Keeper"
Will a scan of my passport be enough?