“ In computing the period of 30 days referred to in section 79(2)(b) of the Act, periods referable to the following matters shall be left out of account – (a) the raising and answering of any reasonable inquiry relating to the requisite return or claim ”
“ For the purpose of determining the duration of the periods referred to in regulation 198, the following rules shall apply – (a) in the case of the period mentioned in regulation 198(a), it shall be taken to have begun on the date when the Commissioners first raised the inquiry and it shall be taken to have ended on the date when they received a complete answer to their inquiry”