My wife is the registered keeper and it was addressed to her.
It has been issued an unusually long time after the parking incident for a car that is not leased/financed etc., although this is to your benefit!
By issuing it so long after the incident, they are unable to recover the charges from the registered keeper under Schedule 4 of the Protection of Freedoms Act (there's a link to it in my signature at the bottom of this post). They can only recover the charges from the driver, and they don't know who that is! Your wife, as the keeper, could therefore appeal along the lines of the below:
Dear Sirs,
I have just received your Notice to Keeper ______ for vehicle VRM ______.
You have failed to comply with the requirements of Schedule 4 of The Protection Of Freedoms Act 2012 (PoFA) namely, but not limited to, failing to deliver the notice within the relevant period of 14 days as prescribed by section 9 (4) of the Act.
Date of event: 28 July 2023
Date of Issue: 20 October 2023
Date of presumed service: 24 October 2023 (POFA para. 9(6) refers)
Elapsed period between event and giving of notice: 88 days
The notice was clearly given well outside of the relevant period of 14 days required for keeper liability as prescribed by PoFA. You cannot, therefore, transfer liability for the alleged charge from the driver at the time to me, the keeper.
There is no legal requirement to name the driver at the time and I will not be doing so.
I do not expect to hear from you again, or your debt collectors, except to confirm that no further action will be taken on this matter and my personal details have been removed from your records. If you do not accept this appeal, you must issue a POPLA code.
Yours etc
If appealing online, she should make sure she does so as the keeper, and does not indicate who was driving (watch out for tick boxes/drop down menus etc.) - keep an eye on your spam emails for their response. If you appeal by post, do so via regular first class post, getting a free certificate of posting from a post office.