VCP10947 | Calculation and notification of the penalty: Time limits
From HM Revenue & Customs · VAT Civil Penalties
Penalty assessments under Section 66 vat Act 1994 are governed by Section 77 of the VATAct 1994.
A penalty for failure to submit an EC Sales list must be assessed
within 3 years of the event that gave rise to the penalty, and
made within 2 years from you having sufficient facts to show there has been a default.
In order to have maximum effect for future compliance, penalties should be assessed at the earliest possible opportunity.