Should I have received a PCN if there were problems with the signs and lines where I parked?

Lines and signs serve to advise the motorist of a restriction and must not mislead. Trifling omissions, however, do not render a sign or line unenforceable.

So long as the sign or marking does not mislead and remains substantially compliant with the requirements of the regulations, the restriction is enforceable.

See Key Case: R (on the application of Herron and Parking Appeals Limited) v The Parking Adjudicator and others (2010) and Letts v London Borough of Lambeth PATAS 1980151656 (1980).