There is no need to argue about the contravention. The plain fact is that they had 28 days from contravention date to serve a PCN, but failed to do so. You should therefore submit reps stating this.Something like: -
Dear Sirs
Re PCN <number> dated <dd/mm/yyyy> for location <location details>
I deny responsibility for payment of the above PCN because it has been served out-of-time. This comes under the statutory grounds of appeal "the penalty exceeds the relevant amount in the circumstances of the case"
As you well know, under the London Local Authorities & Transport for London Act 2003, a period of 28 days is allowed for serving a PCN from the alleged contravention date. The date of the alleged contravention on the above PCN is 29th August 2024, over 5 months ago. However, just in case you are uneducated in the LLA & TfL Act 2003, I attach it for you to read.
https://www.legislation.gov.uk/ukla/2003/3/contents/enactedYours faithfully