SolvedCH74300 | Penalties for Failure to Notify: How to process a penalty: Enforcement of a penalty
From HM Revenue & Customs · Compliance Handbook
The penalty for a failure to notify, see CH71220, must be paid within 30 days. The 30-day period begins on the date the penalty assessment is issued.
A penalty assessment
may be enforced as if it were an assessment to the underlying tax, and
shall be treated, for procedural purposes, in the same way as an assessment to the underlying tax except where there are specific rules for penalty assessments, such as time limits, see CH74200, and
may be combined with an assessment to the underlying tax.