From what you described I understand it is a private land. Can you advise if you paid / obtained valid ticket and presented it on the dashboard? Have they provided you with photographic evidence of the front (dashboard) of your vehicle?
Also it worth noting that legally those are not notices, but invoices. Invoice for a breach of contract.
If you sure your appeal was rejected by Nexus (I am very surprised they responded so quickly), your next step is https://www.popla.co.uk/
N.B. I would treat VERY carefully the above “Absolutely no” suggestion. Yes, it does work for many, myself included, but you must be aware you take a legal risk here.
Sent from a mobile device.
Apologies for briefness and spelling mistakes.
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