SolvedCH72620 | Penalties for Failure to Notify: Calculating the penalty: Potential Lost Revenue: General
From HM Revenue & Customs · Compliance Handbook
The potential lost revenue (PLR) for failure to notify, see CH71220, is the amount of any tax or duty that is unpaid or the tax the person is liable for as a result of the failure.
There are specific rules for calculating the PLR for a failure to notify for most of the main taxes and duties. See CH72660 onwards for the methods for each of the different obligations.
When you calculate the PLR for a person’s (P)’s failure to notify, you do not take into account any tax overpaid by another person because of P’s failure. The only exception to this is where that other person is allowed to adjust their tax liability by reference to P’s liability. There is an example of this at CH72640.