OP,
This was all done via email - they confirmed receipt of the appeal by email. The address registered to the payment made for the 16 Aug was correct.
How could the appeal have been emailed and yet the sender not have a copy?
Online I could understand, but email?
You are behind the 8 ball. A SD may only be submitted on one of these grounds:
Statutory Declaration
This is a formal legal declaration and can only be made on the grounds that a person:
did not receive the Penalty Charge Notice in question;
made representations to Transport for London but did not receive a rejection notice from them; or
appealed to a Road User Charging Adjudicator against the rejection by Transport for London of representations made by them but had no response to the appeal.
TfL will claim, correctly, that they obtained the RK's address from DVLA which was used for all subsequent notices.
Somehow your wife is the Road User Account Holder at address B, but you are the registered keeper at address A. She 'appealed' the PCN without telling you and presumably because she's the account holder. IMO ONLY if she made clear in the reply that TfL should use the account holder's address for their response would you definitely succeed with a SD.
If you have nothing to add as regards the email's content, then I don't see how you could convince TEC to reset matters. IMO, you need to introduce this as proof in your SD.
Why not get your wife to contact TfL to obtain a copy ASP? She could submit a Subject Access Request, but this could take some time for TfL to fulfil.
As it stands, it's your neighbours and your car which are in jeopardy. They cannot seize goods in your residence until they've served the mandatory notice.