It would seem to me that an argument that the PCN is defective in not giving unambiguously all the information required is not a lawful PCN thus cannot be enforceable would have merit
Arguments re the website giving different information would have to evidence prejudice
At the end of the day the council cannot send a letter saying you owe us so pay up they must comply with the requirements of the regs
On a personal note I have stopped looking at these as they are invariably taken off the forum to be delt with by individuals. The collective mind seems to be no longer wanted