s 40C Review by HMRC
(1) HMRC must review a decision if— (a) they have offered a review of the decision under section 40A, and (b) P notifies HMRC accepting the offer within 30 days from the date of the document containing the notification of the offer. (2) But P may not notify acceptance of the offer if P has already appealed to the appeal tribunal under section 40G. (3) HMRC must review a decision if a person other than P notifies them under section 40B. (4) HMRC shall not review a decision if P, or another person, has appealed to the appeal tribunal under section 40G in respect of the decision.