VATF45290 - Basic interventions: matters to consider when determining whether to use a civil intervention: assessments and penalties: raising penalties in particular circumstances: assessment time limits
The penalty assessment must be made within two years of the denial decision being issued. An appeal against the denial decision does not extend this period.
The same time limit applies for the date by which a company officer liability notice must be "given" (i.e. the date it is received or deemed to be received by service through the post).