Free Traffic Legal Advice

Hi I'm looking for some advice/guidance on my present situation with a failed appeal for a PCN. I've seen this site recommended online and would be really grateful for any help.

-I used a car park in Leeds Kirkstall twice to visit a different PureGym while my usual PureGym was being renovated
-Puregym app advertisrx the site as having free parking which I've screenshotted as part of my appeal evidence
-There was no signage at all from the private parking company stating a need to validate parking only a need to pay during the hours I visited which didn't apply to me as was using the car park with a valid reason for free, there also wasn't any clear signage in the gym itself (if there was any at all), which was unstaffed at the times visited
-I received two PCNs as a result from Group Nexus
-I provided evidence from the Puregym app of my visits matching the parking stays to show this was a legitimate use of the car park each time
-One of the PCNs was waived by Nexus, for the other I was asked to pay a reduced £20.00 fee - as I had not been alerted otherwise in my eyes between visits these effectively were the same instance of the same problem. I felt any fee was unfair
-I appealed the decision with POPLA
-Group Nexus sent through supporting 'evidence' on the POPLA of the signage which is what alerted me to the fact there was no reference to a requirement to validate parking signposted
-29/07/25 POPLA upheld the PCN "The parking operator has advised there is a third-party agreement with Puregym for gym users to be able to register for parking at the site. As this is a third-party agreement there is no requirement for this to be on the signs in the car park. The parking operator is not responsible for Puregym not advertising this within the gym, app or their website, the appellant would need to raise this with Puregym directly. I note that the appellant has advised the staff at the reception did not advise them off the parking restrictions, the staff at the venue are a third party and under no obligation to inform motorists of the parking restrictions." (I mentioned no-one had told me to validate the parking, but have since realised this is because the gym is unstaffed at night)
-29/07/25 the same day I emailed Group Nexus asking them to reconsider and that I'd be happy to pay the £20.00 to draw the matter to a close, in this email I mentioned "I've tried to make payment today but have been unable as I'm no longer afforded the option on your website. Please make this facility available so we can bring this process to an end."
-08/09/25 Nexus have finally replied to that email (outside of their own automated responses specified timescale of 28 days) saying I now owe £170.00 due to not paying the original charge in 28 days of the decision, with no reference to my explanation in the email prior that I didn't have the option to pay. This ends by saying "we are sorry we are unable to enter into any further correspondence about this matter". I'd wrongly assumed they'd given up.

I'm wondering:

-Is it likely this would go to court
-Would I be likely to win a court case over this
-If I lost a court case and were asked to pay a country court judgement, would this affect my credit history even if I paid this right away
-How much roughly would the extra court costs be if I had to pay these

Just generally I wanted to know what would be my next best steps, my local Citizens Advice Office isn't taking emails and I think I'd struggle to explain this well over the phone. I'm wondering if I should respond to Nexus particularly to point out I wasn't able to make payment on 29/07/25 when I'd tried. Ideally I'd not pay anything as I don't feel this is justified. Plenty of people online seem to suggest ignoring these charges as they rarely go to court but I'm also slightly worried about what a debt collection process would look like as don't want me and my partner to be harassed.

Many thanks for taking the time to read ❤️