If a person contravenes section 7 he shall be guilty of an offence.
Without prejudice to subsection (1), if a person executing or causing to be executed any works in relation to a listed building under a listed building consent fails to comply with any condition attached to the consent, he shall be guilty of an offence.
In proceedings for an offence under this section it shall be a defence to prove the following matters—
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A person who is guilty of an offence under this section shall be liable—
In determining the amount of any fine to be imposed on a person convicted . . . of an offence under this section, the court shall in particular have regard to any financial benefit which has accrued or appears likely to accrue to him in consequence of the offence.