We have to deal with the law as it is, not as you would like it to be. As far as the law is concerned you're banged-to-right on the contravention and that's the end of that. However there are other grounds of appeal available, and one has been identified by HCA.
Here is a draft you can use:
Dear London Borough of Brent,
I challenge this penalty charge on the ground of a procedural impropriety. Regulation 11(2) of The Civil Enforcement of Road Traffic Contraventions (Representations and Appeals) (England) Regulations 2022 provides that upon being required to pay the penalty charge, I should have been immediately been informed of my rights under regulations 11(3) and 11(4), but the relevant statutory information was not provided to me.
In light of this procedural impropriety, the penalty charge must be cancelled.
Yours faithfully,
Send the representations via email, you should get an automated acknowledgement.