The prevalence of discounted payments and, frankly, bullying tactics to get people to pay them to avoid court action has turned the entire system into a massive machine that just generates revenue for everyone but the legal system itself. The parking sector was regulated almost out of existence around 10 years ago, but like cockroaches they have survived and use these bullying tactic fairly heavily, though with less legislation on their side they tend to not take anyone to court despite repeated threats. It's just much easier for the average person to stump up £60-£150 than deal with a day in court. Especially when there is essentially a punishment for going to court if you lose: Loss of the 'discount', the awarding of costs against you and in some cases more points on your driving license or other endorsements than if you'd just ticked a box and sent a cheque.
It doesn't feel like a justice system. And the worry is, as we've seen with the railway, there is more incentive to get people processed and collect the fines than actually delivering justice to those really worthy of a day in court, and that can mean a lack of evidence when the system becomes lazy. Plenty of cases of incorrectly configured speed cameras that had no legal basis of operating that only came about because someone bucked the trend and went to court, but anyone who ticked the box and paid the fine wont see a penny back.
Zero losses are something that no court should entertain. It's farcical that you can pay more in fees than what your alleged transgression has cost the company. And does reinforce the point that it's just become a money-spinner.
As to fixing it: In the first instance I'd like to see it made a legal requirement to log, publicly, the numbers of private prosecutions threatened. And of those how many were settled, dropped, paid or went to court with the same detail about court actions. £ values included, too. Get that data and expose the scale of the problem, and then push through legislation to stop the bullying/threatening tactics. Make it so the mere act of demanding money due to a breach has to come from someone actually trained in law, push up the costs and make the companies involved much more likely to scale back the operations.