You have not reached the “it has to be paid” stage at all, despite what you are thinking.
First, do not worry about the Times24 versus NCP naming. Times24 UK Limited is essentially NCP by a former/alternative corporate name. The fact the rejection is on NCP letterhead but signed off as Times24 just shows how slapdash they are with their stationery, it is not a magic “wrong company” get-out. Legally it is the same outfit behind the charge.
The important bits are these:
Gatwick is airport land subject to byelaws, so it is not “relevant land” for the Protection of Freedoms Act. That is why, in general, my stock advice is for the keeper never to say who was driving. If the driver is not identified, there is no lawful route to transfer liability from an unknown driver to the keeper. In your case, you have already appealed in a way that tells them who was driving, so the PoFA keeper-liability angle has largely gone for this particular ticket. That does not make the charge inevitable; it just means we now argue on different ground.
NCP/Times24 are not saying you failed to pay. Their letter is very clear that this is being treated as “misuse of the parking area” and that the alleged breach is “Express Pick Up Bay – express pick up only, no unattended vehicles at any time.” In other words, they are trying to say that even though you were a legitimate pre-paid customer of the multi-storey, you happened to stop in a bay that they regard as a special “no parking, no leaving the car” area and they want to punish that with a £100 contractual charge.
For that to stick, they need to show that there was a clear, prominent contractual warning at the point you drove in and at or around that bay which:
1. Made it obvious that this particular bay or area was under different rules from the rest of the car park.
2. Spelled out that leaving the car unattended, even briefly, was not allowed.
3. Stated in large, prominent text that the price of ignoring that term was a three-figure parking charge.
Your description is that the signage is “naff” and that you did not realise this was some sort of “express drop-off” bay; you thought you were simply parking in the car park you had pre-booked and paid for. That is exactly the kind of factual background that casts doubt on whether any clear contract to pay £100 for leaving the car unattended was ever formed.
The photos and layout will matter. If this bay is physically within the body of the normal multi-storey, and the general impression from the pre-booking is “you have paid, park in car park 6, level 4”, then NCP/Times24 have to overcome a lot of confusion that they themselves have created. Vague or cluttered signs, small print, wording that reads more like a prohibition (“no unattended vehicles”) than a clear offer (“you may leave your vehicle here subject to a £100 charge if you breach these terms”) all help you. It makes it easier to argue that a reasonable motorist in your position could not and did not agree to a penalty for parking there.
The airport context is also worth mentioning. Gatwick has its own byelaws system; if the airport genuinely wanted to prosecute people for breaching those, that would be a matter for a magistrates’ court and any fines would go to the public purse, not to NCP/Times24. Instead, NCP/Times24 have chosen to run this as a private contractual scheme for their own profit. That underlines that this is not a “fine” in any legal sense, just a disputed invoice dressed up in official-sounding language and sent out in bulk.
Where does that leave you now?
You still have a live POPLA code. Using POPLA will mean you lose the mugs discount if you lose, but you gain a completely free extra stage where the operator has to put their cards on the table and you can test their evidence without paying a penny. POPLA is not perfect, but plenty of Gatwick airport cases have been won on signage and contractual issues, particularly where pre-booked parkers have been caught out by confusing bay layouts.
Even if not successful at POPLA, you are not bound by their decision and you do not pay. Where this would eventually be won is if/when they issue a county court claim. In the vast majority of cases, they never progress all the way to a hearing and most cases are either struck out or discontinued. Of the very few that ever get as far as a hearing in front of a judge, most are won.
So, if you are up for a fight rather than just paying to make it go away, the sensible route is:
Treat the driver-identity point as water under the bridge for this case. It was a mistake to reveal the driver, but it is done. Learn from that.
Base your POPLA appeal on the real weaknesses: unclear and inadequate signage, the confusing layout of the “express pick up” bay inside a pre-booked multi-storey, the lack of any clear, prominent warning about a £100 charge, and the airport/byelaws background to show that this is a commercial scheme, not any form of official fine. You should also put the operator to strict proof that have a contemporaneous and valid contract flowing from the landowner to operate and issue PCNs in their own name at the location. You'd be surprised at how many firms continue to operate on expired or invalid contract and therefore have no standing to even operate, never mind issue PCNs and to try and sue.
Do not be spooked by their wording about “you must choose to pay or appeal”. They always say that. You are perfectly entitled to take it to POPLA. If you are successful, the charge is gone. If not, you are in no worse position than if you had given up now, other than losing the time-limited mugs discount, which is what they use as leverage to make people cave in.
In short, you have by no means reached a point where this “has” to be paid. The keeper-liability route that I gave as a template would have been an easy win if the driver had stayed unnamed, but even with that mistake made, you still have decent contractual and signage arguments to run, and Times24/NCP are far from infallible when pushed to prove their case.