So the discount expires on midnight at the end of 29 October 2023. If the amount owed on the council website goes up to £70 before then, you have a winning appeal on the penalty exceeds ground (in which case you will need a timed / dated screenshot showing the amount due, I can do that for you).
That also gives us a bit of time to consider other issues so let's start with the basics: did you not see the signs, or did you not know what they mean?
For reference, here's the video: