I thought so! I had a job interview with Gladstones a couple of years ago and I know their business model and their clients being the “parking enforcers” of the World very well!
It appears that they issued Part 7 Court Proceedings against you for the full amount of the penalty. Unfortunately, you did not receive the Court Proceedings as you had changed address and were therefore unable to respond to them by serving and filing an Acknowledgement of Service or a Defence. Gladstones therefore requested a Default Judgment from the Court which has been granted. You have only discovered the Default Judgment at a much later date as it has been registered against you and has adversely affected your credit rating.
You have two options of resolving this matter.
You can pay the amount of the Default Judgment in full, including the original damages claimed, interest and legal costs. You may then send proof that the Judgment has been satisfied to Credit Reference Agencies such as Experian as well as your Bank and it will be removed from your Credit Record.
The other option is that you make an Application to Court as soon as possible for the Default Judgment to be set aside on the grounds that you were not actually served with it and you have a realistic prospect of defending the parking company’s claim on its merits.
However, the amount of damages of the Default Judgment will mean that it is a Small Claims Court matter and therefore parties cannot recover legal advisors’ costs even if they are successful at a fully contested hearing. While you are free to instruct your own solicitor at cost, their fees are likely to be swallowed up by the low amount of damages in issue making this claim uneconomic to defend.