If you feel you are being harassed by the parking operator and there is no basis to their claims, you can at the defence stage, put in a counterclaim. This would normally be for a tort such as the misuse of personal details.
If you feel you want to mount a counterclaim, then drop us a line at firstname.lastname@example.org and we'll help.
The MoneyClaimOnline guide says this
Counterclaim – the defendant wishes to dispute the full amount of the claim and also files a claim against you. The defendant will need to pay a fee to make a counterclaim. If the fee is not paid, the case will proceed as if a full defence has been filed. Once the fee has been paid, the case will be transferred to a County Court Hearing Centre (please note that if you withdraw your claim the case will continue on the counterclaim alone). You will also need to file your response to the counterclaim and a directions questionnaire. Failure to do so could result in the defendant applying to enter Judgment against you.
So a counterclaim is two claims in one. Even if the parking contractor drops out, your own claim will continue and the parking contractor will either have to defend or settle. It's a good way of getting their attention if you feel they are harassing you at your home. Cost is only £25.