OP, I made the point earlier that the sign in the bay is specified for on-street use only.
Others have made the point that the effect of this sign and the fact that failure to comply could result in the imposition of a penalty charge must be conveyed clearly at the site.
You were asked to obtain photos of these signs, but we haven't seen any.
The council say their noticeboards carry this info but have not provided photos.
The order can say what it likes, but unless the effects of failure to comply with the order are displayed clearly at the site then its provisions are of no effect, this is not a guessing game.
You have the NTO. The last day of the 28-day period is 11 October, not 12th as stated in brackets in the body of the NTO.
Why don't you contact the council, refer to their reply to your informal reps and ask them for a photo of what it is they say conveys the effect of the on-street traffic sign in the Ts and Cs of use of the car park.
I note that reference has been made to the discount being re-offered if reps are submitted within 14 days, however, there's no reference to this in the NTO(although we've only seen the front page, pl post the remainder). IMO, it would be a breach of the council's public law duty to act fairly if they were to offer the discount contingent upon a policy condition which has not been brought to the owner's attention. As I said above, this is not a guessing game. They may offer the discount in the event of unsuccessful reps whenever they're submitted, this is the exercise of discretion and perfectly fine.
IMO, you need details of the signs and the Ts and Cs and should make an effort to obtain these before