The Child Support (Maintenance Assessments and Special Cases) Regulations 1992

[F12.  A relevant decision may be reviewed by a child support officer, either on application by a relevant person or of his own motion—

(a)if it appears to him that the absent parent has at some time after that decision was given satisfied the conditions prescribed by regulation 28(1) or, as the case may be, no longer satisfies those conditions; or

(b)if it appears to him that the relevant decision was wrong in law or was made in ignorance of, or based on a mistake as to, a material fact.]