received PCN from UKCPM - appeal or ignore

[silly1]

I have received PCN from UKCPM for parking in the reserved area without permit, I didn't see the signage at the time of parking and thought its standard parking so paid for forking for the duration of stay. but then received notice after few days. I appealed to them but appeal was rejected as expected.

any suggestions on appeal to IAS? I was thinking to ignore them but not sure if these private operators are now taking court actions?
Thanks in advance.