IMO, Get on the front foot pl.
Email(copy to yourself) dataprotection@carflow.co.uk
You require copies of all notices and correspondence, whether issued by you or your agents, in respect of Parking Charge number **********. Email service would suffice.
Please note, my address for all written correspondence is now ************.
You should delete address ******** from your records.
And provide some proof of identity and address pl, maybe a photo ID driving licence?