Free Traffic Legal Advice

I added my wife's car onto my TFL account the day before she traveled through the tunnel but didn't realise I also had to add it to Auto Pay.

She's now received the £90 PCN.

Before we attempt a politely challenge via the TFL website stating I didn't realise I had to add it to Auto Pay, is there anything else to consider?

I've tried getting a report from TFL online showing the date the car was added to the main account but it doesn't look possible

My Auto Pay account was opened a few years ago when ULEZ expanded and I don't remember having to go through 2 steps when adding my car originally, maybe I'm just forgetful!

thanks

As usual, for meaningful advice please have a read of
https://www.ftla.uk/civil-penalty-charge-notices-(councils-tfl-and-so-on)/read-this-first-before-posting-your-case!-this-section-is-for-council-tfl-dartme/

and post up there
(use
ibb.co or https://imgpile.com/
for posting images.
Wherever possible, use the BBCode.)

a brief account of the circumstances which led to the PCN,
all sides of the  PCN (only redact yr name & address - leave everything else in),

a GSV link to the location,
and any council photos/video.