SolvedCH185080 | Dishonest tax agents: how to process a penalty: enforcement of penalties
From HM Revenue & Customs · Compliance Handbook
A person can be charged
a penalty for failing to comply with a file access notice, or
a penalty for dishonest conduct, or
both.
These penalties must be paid
within 30 days from the date when we issue the penalty assessment, or
if the person appeals against the penalty, within 30 days from the date when the appeal is withdrawn or determined.
These penalties may be enforced as if they are income tax charged in an assessment and due and payable.