Let's start by putting the PCN the right way up:

Given that it's issued under the now defunct 2007 regulations, it's a no-brainer to carry on. The signage is correct, but the council only gets one shot at issuing the PCN, and I can't see the tribunal upholding a PCN that has been issued under legislation that was abolished last year.
There's also the fact that the PCN wording is duplicitous and it doesn't specify what contravention you are actually being accused of,
Let us know when you get the Notice to Owner and I'll draft a representation for you.