You may wish to share a draft before submission.
Also, don't expect POPLA to accept your appeal - not necessarily because it is without merit, but because POPLA rarely go for the 'forbidding signage' argument.
I have drafted my appeal before submission as follows (basically a cut and paste of prior posts, plus some further explanation)
I would be very grateful for any further pointers before submitting to POPLA. Thanks

"I am appealing as the KEEPER of vehicle registered xxxxxxx.
I believe that this ticket has been issued unfairly and wish to contest it based on the following two legal principles concerning contract formation.
Ground 1 - PoFA 9(2)(e)(i) failures
Schedule 4, Paragraph 9(2)(e)(i) of PoFA 2012
This paragraph mandates that for a parking operator to hold the vehicle's registered keeper liable for a parking charge, the Notice to Keeper (NtK) must include:
An "Invitation to Pay": The notice must explicitly invite the keeper to pay the unpaid parking charges.
Exact Wording: The wording must clearly convey this invitation and mere implication or indirect suggestions are insufficient. The act requires strict compliance, meaning that any failure to fully incorporate this invitation renders the notice non-compliant with the requirements of PoFA 2012.
Non-Compliance Issue: The NtK fails to include a clear "invitation to pay", or any synonym of the word "invitation", this omission is a breach of Schedule 4, Paragraph 9(2)(e)(i). Even if the notice suggests that payment is required, without an explicit invitation directed towards the keeper to settle the charge, the notice does not meet the exacting requirements of PoFA 2012.
Significance of Full Compliance
Strict Liability: The law mandates full and exact compliance with the specified wording and content outlined in PoFA 2012.
Partial or even Substantial Compliance Insufficient: Even if the notice largely complies with other requirements, the absence of a clear invitation to the keeper to pay is a significant flaw. The operator cannot rely on partial or even substantial compliance — every element as specified in the legislation must be present and correct.
Consequences for the Operator
Challenge Basis: If the notice is found to lack this crucial element, it can be used as a basis to challenge the parking charge.
Keeper Liability: The operator cannot transfer liability to the keeper.
Conclusion
In summary, the PCN does not include an explicit "invitation" for the keeper to pay the charge and therefore is not fully compliant with Schedule 4, Paragraph 9(2)(e)(i) of PoFA 2012. Since the law demands strict adherence, any omission, even if minor, invalidates the notice and relieves the keeper of any obligation to pay.
Ground 2 – Parking was forbidden during the times the vehicle was parked, thus no contract was formed as no consideration was offered by Parking Eye (the sign isn’t making a genuine offer to park for £100 when the store is closed)
For a contract to be formed, there must be a valid offer and acceptance, as well as consideration.
In this case, no contract can be formed when parking is explicitly prohibited during certain hours or under certain conditions.
Where parking is forbidden, there is no genuine offer being made to park the vehicle.
Consequently, without an offer, there can be no consideration, as the driver is not receiving any benefit for which they would be expected to give something in return.
By issuing this parking charge, it implies that a contract has been formed between the driver and the parking operator.
However, as parking was not permitted at the time, no such contract could exist.
When parking is prohibited, the mere presence of signage indicating restricted parking cannot be deemed an offer to contract, and therefore, any such charge is unenforceable due to the absence of mutual agreement and consideration.
There are legal precedents that touch on the idea that no contract is formed when parking is forbidden during certain hours, or when there is no genuine offer of consideration. One key point is the absence of an offer and no consideration when parking is prohibited or when certain conditions, such as a store being closed, are in place.
Vine v London Borough of Waltham Forest [2000] EWCA Civ 106: In this case, the Court of Appeal ruled that a motorist cannot be deemed to have agreed to the terms of a parking contract if they were unaware of the terms. If parking is prohibited, then the motorist is not accepting an offer but rather breaching a restriction, and no contract is formed.
Thornton v Shoe Lane Parking [1971] 2 QB 163: In this case, Lord Denning held that an offer must be clear and capable of being accepted by the driver. If no clear offer is made, no contract is formed. When parking is expressly prohibited during certain hours or in specific circumstances, no valid offer can be made, thus preventing a contract from being formed.
ParkingEye Ltd v Beavis [2015] UKSC 67: This is the leading case on parking charges, but it also reinforces the point that contracts in these situations are formed based on an offer of parking. However, if parking is not permitted at certain times (such as when a store is closed or outside designated hours), no valid offer is made, and no contract can be said to exist. The judgment implies that for a charge to be enforceable, a valid offer and acceptance must be in place, meaning the signage must constitute a genuine offer.
Conclusion
Parking was prohibited during the times the vehicle was parked, thus no contract was formed as no consideration was offered by Parking Eye. Hence the PCN is unenforceable due to the absence of mutual agreement and consideration.
I kindly request that you review both grounds I am contesting the PCN against."