If there is any good news at all, it is that you have now paid all there is to pay, therefore submitting representations against the PCN, tow, and the excessive storage charges is a no-brainer. In addition, registering an appeal at London Tribunals as well when you are inevitably rejected by the council is also a no-brainer, because there would be no additional costs or penalty in doing so.
However, whilst you have posted some photos, we need to see those the CEO will no doubt have taken. This is because in your narrative, it is clear that you didn't see any suspension sign when you parked in broad daylight, and when you returned to drive your car some days later and found it missing, there were also no suspension signs.
So please give us a GSV link to the exact location of parking, and if you can, find the council photos, download them and post them here. It is more than likely that the suspension sign was erected after you parked, in which case you were parked legally when the suspension sign(s) was erected. Councils are notoriously bad at giving advance notice of suspensions.
You should now write some representations and post them here for review. This needs to be based on your narrative here, namely that you saw no suspension signs in position when you parked on <date>, and on return to your car on <date> found the car missing and then found out the car had been towed from a supposedly suspended parking area. State that you deny responsibility for the PCN and subsequent tow and storage costs as the contravention did not occur because there was no sign advising of a suspension.