So, I've tried to search if anything like this has happened before, but not really sure on the right keywords to search correctly.

At this time, I'm far down the line, parking company has issued claim with court and I've already submitted my defence before finding this website. I'm now waiting to hear back on court dates but I'm interested to see if any of the below has happened before and any precedents.

My partner works for a supermarket and used our car, that is registered in my name, to go to a training course at a store that was not their normal one. But it is a local one so visited it many times for personal use.
They parked up, when in the store, put their name and the car details in the visitor book. So expected thought is job done, no need to worry about hitting the 2hr limit on the car park. This was also done by their colleague, in fact they parked next to each other and my partner drove into the car park behind the colleague and then left in front of them.

Few weeks later, I get a parking notice, so too did the other colleague.
This was raised with the store the training was done at, and it turns out that the car park is split in jurisdiction for parking companies. The store parking company covers 3/4 of the car park, the other 1/4 (for the other stores in the area) is covered by Parking Eye. Both my partner and colleague had entered the car park on Parking Eye's side and then parked up on the row before the supermarkets area.
On a personal use level, we never knew this (looking back at the car park today the signage for the parking does change, but there's nothing clearly stating where the line is, though the area of the car park that makes them linked has recently had new massive cameras installed) if you saw it you'd just think it was one car park.
On a work level, my partner and colleague were never told of the separation and no attempt was made to check that they'd parked in the correct area.

However, a manager at the store took a copy of both the parking notices and spoke with the security guard who said they'd get them cancelled.

The colleagues was cancelled.

Mine went on to reminder notices, at which point I used Parking Eye's portal to explain that I wasn't driving the vehicle and that the manager had been in touch about this. We also when back to the store, who again took the notice to the security guard.
On the back of my points raised to Parking Eye, they sent a rejection letter due to insufficient evidences. They did then list POPLA, however we didn't raise this with them as we were liaising with the store and they with the security guard. Every time we were told by the managers at the supermarket that the parking notice was being cancelled, but clearly never was. In fact at one point they referenced that there was confusion between the notice being in my name, but the request coming from my partner.

I'm rather annoyed with myself because if I'd known it would go this far I would have skipped using the store managers as liaisons and gone directly to the store so I was their while they spoke with the security guard so I wasn't hearing everything word of mouth, and could have got something written beyond emails between the managers and my partner.

This has resulted in it going all the way to the court now. I've got written statements from the two manages at the supermarket confirming the actions they did and information they were told. I've got the confirmation that the other colleagues parking notice was cancelled. But I don't have anything from the security guard they spoke to so I do feel I am lacking evidence to equivocally prove my position.

Has anything like this happened before? Do I have a leg to stand on with the other notice being cancelled?

It's going to court either way, just trying to see if there are other precedents for situations like this. If I lose and have to pay I will, but really don't feel I should based on the other being cancelled.

Thanks in advance for any thoughts/information you have.