“49 Late notice of appeal 49(1) This section applies in a case where- (a) notice of appeal may be given to HMRC but (b) no notice is given before the relevant time. 49(2) Notice may be given after the relevant time limit if- (a) HMRC agree, or (b) where HMRC do not agree, the tribunal gives permission. … 49(8) In this section “relevant time limit”, in relation to notice of appeal, means the time before which the notice is to be given (but for this section).”