I think the collateral argument needs to be re-thought. In the cited decision, Adams v LB Havering the issue was the wording which included the use of the term Charge Certificate in the same sentence as making representations.
I think Wandsworth have been smart here. Their PCN does not refer to a CC, even less making representations in this context, as indeed is correct, they simply state what's mandated by the Act i.e. if payment is not made within the 28-day period..a period which is stated beforehand, namely 28 days beginning with the date of issue of the notice.
IMO this is distinguished from the cited decision in such a way that I think there is great doubt as to whether you would succeed on this point.