You have a lot of avenues open to you and provided you handle this appropriately you won't have to pay anything, regardless of the outcome of any appeals.
The deadline for appealing to UKPC is 18 January. Use the time before then on the so-called "Plan A", complaint to the landowner. The car was parked at Beckton Triangle Retail Park which is managed by Mike Craig of The Spencer Craig Partnership - Phone: 020 8498 9292 Email: info@spencercraig.com. They are closed till 2 January but you could email him now and follow up with a phone call if you don't hear back by the middle of next week.
Something along the following lines should do:
Dear Mr Craig,
I am writing to you as I understand that you are the managing agent of the Beckton Triangle retail park.
I am a loyal customer at the retail park. I am also the holder of a disabled motorist’s blue badge and have attached copies of its front and back. On [ ] December 2023, I shopped at the retail park and the car in which I travelled was parked in a disabled space with my blue badge and clock on display. Despite that, your parking contractor issued me with the attached PCN.
I would like to continue to shop at the retail park but cannot afford to if your parking contractor penalises me for doing so.
I shall be grateful if you will instruct your parking contractor to cancel the PCN by way of reasonable adjustment pursuant to the Equality Act 2010.
Yours faithfully,
If you have proof of shopping such as receipts, attach them as well. Be careful not to reveal who actually drove the car as this could be relevant at a later stage.
Come back for more advice if you don't get anywhere with Plan A by 10 January and we can move to Plan B - appeals.