Sorry, but you haven't given us much to go on at all. The Newlyn letter looks legit.
However, it looks as if you have not received a postal traffic/parking enforcement document, maybe a PCN, or a Notice to Owner, (if the contravention was for parking). So it is of paramount importance that you post up all the documents you have received, with only name and address redacted.
Any appeal option you had is now expired, and you cannot now appeal the original PCN until you can get the process reverted back to the PCN stage. There is only one avenue open to you to try to revert the process back to the original PCN, and that is to submit an Out-of-Time Witness Statement. That is what the TEC court officer told you to do, (Forms TE9 and TE7). So why did you only submit a TE9 ? You were out-of-time, because bailiffs had been instructed, and this can only happen after the period to respond to an Order for Recovery has expired, so you had to also submit the TE7; without it your application will be rejected.
I also suggest you go and look at your V5C Registration Certificate for the vehicle and check the address is correct in all detail and is the same as when the alleged contravention occurred. If you have failed to update your V5C when changing address, it is unlikely submission of an OOT Witness Statement will be accepted, because the council can object to it and invariably do so.