They've got hearts of stone, haven't they ?
Had a Notice to Owner - and did the informal appeal. Just got a rejection.
Sorry, but it's not clear if that letter is a rejection for reps against the Notice to Owner, or reps against the original PCN. This is important, because you must not ignore an NtO.
Taking the matter to London Tribunals means the full PCN penalty will be in play. If you're happy with that then go ahead, but at the moment, I'm struggling to think which of the statutory grounds for an appeal would apply. You were parked in a loading bay, so the only exemption would be boarding/alighting passengers. I'm not sure if your narrative fits that particular exemption. Of course the council could apply discretion but here they haven't, to their eternal shame, but that's Great Britain 2026, isn't it ?
If you're minded to pay the discount, don't miss the deadline in their letter, but if you can, wait a bit to see that others might suggest.