29(1)If a person becomes liable to a penalty under Part 3 or 4 of this Schedule, HMRC may assess the penalty.
(2)But, in the case of a penalty under Part 4, they may only do so if a conduct notice has been given to the person and either—
(a)the time allowed for giving notice of appeal against the determination has expired without notice of appeal being given, or
(b)notice of appeal against the determination was given within the time allowed, but the appeal has been withdrawn or the determination confirmed.
(3)Paragraph 7(4) applies for the purposes of sub-paragraph (2)(b).
(4)If HMRC assess a penalty, they must notify the person.