CBTM05290 | Failure to disclose: Disclosure by a third party
From HM Revenue & Customs · Child Benefit Technical Manual
A disclosure by an appointee, a signing agent, or a partner in CHB overpayment cases, is equivalent to a disclosure by the claimant. Where such an arrangement does not exist, disclosure by a third party is sufficient only if
the information is given in connection with the claimant’s own benefit to the relevant benefit office, and
the claimant is aware that the information had been given in that way, and
in the circumstances it is reasonable for the claimant to believe it is unnecessary to take any personal action.