You need more balls for this one, because it will take some time and effort, plus some costs up front. Because this may end up having to go to court, there is also no guarantee that you will get your money back.
First, read up on my three previous posts, explaining how UKPC regularly charge more than they are allowed to for Parking Charge Notices. G. Bozzino neatly sums up the position in his FoI request as follows:
Under Contract Law a provider of services may only claim an amount equivalent to actual loss or a pre-estimate of loss if a contract is breached; they may not demand a punitive sum.UKPC regularly charge extra amounts they are not entitled to, such as wages, office running costs and kickbacks to the land owner.
If this situation applies to any parking charge you have paid to UKPC in the last six years then you can claim your money back.
Write a 'Letter before Action' to both UKPC and the landowner pointing out the above and asking for your money back.
If this does not work, file an MCOL claim naming UKPC and the landowner as defendants. This will cost £25 (current court costs are explained here). Ask for a copy of the contract between UKPC, and a full breakdown of how the actual loss or pre-estimate of loss is arrived at.
If they do not pay up, pay for a court hearing. The allocation fee is waived for claims under £1500, but there is a £25 hearing fee. As claimant you get first choice of court. The defendant is allowed to ask for a different court and if you do not agree a judge will decide. Going to 'their' court allows you to charge reasonable travel expenses if you win, so you might prefer to travel.
Turn up for the hearing. If they do not, you will get a default judgement against them. If they do, then it depends what documents they filed. If the contract shows kickbacks to the landowner it should be a slam dunk. If they refuse to provide a contract, or try and argue the costs are genuine then it depends on your arguing power and the view of the judge. The odds will be heavily in your favour, but judges can be temperamental.
If you win, you can ask for costs. This is the small claims court, so they will be limited mostly to your travel costs. If you lose, you will have to pay their costs, which are similarly limited.
If they still do not pay up, you may have to get a bailiff to seize goods. This will cost at least £100, and maybe more. If the landowner is a big company, it may be far easier to get them to cough up than it will UKPC.
If you do get the money back, this will also include any extras such as bailiff fees, court fees etc. Well done!
As you can see, this is not for the faint hearted. However, if you feel strongly about this, it is a fairly straight-forward process.