should we be expecting TfL's reply in the post as well?
It has to come by post. Written on Friday you said (date in status timeline?). If posted on Friday, should arrive tomorrow or Tuesday. Given the state of the Royal Mail, I'd give it a few days before chasing it up. (I don't know if they will email it on request).
You have checked against both PCN numbers?
Until we see the rejection we do not know what errors may lie therein.
@cp8579 may well knmow if there are any fatal errors in the small print of TfL's ULEZ PCNs
(Posts Replies #2 and #14 on page 1 above).
I think I'd like to pay this and get it out of the way today,
You don't want to pay today and close the case only to find fatal errors in the Notices of Rejection when they arrive.