“ An order under this section may provide that a taxable person of a description specified in the order shall be under a duty- (a) to pay, on account of any VAT he may become liable to pay in respect of a prescribed accounting period, amounts determined in accordance with the order, and (b) to do so at such times as are so determined ”
“ For the purposes of this section a taxable person shall be regarded as in default in respect of any prescribed accounting period if the period is one in respect of which he is required, by virtue of an order under section 28, to make any payment of account of VAT and either- (a) a payment which he is so required to make in respect of that period has not been received in full by the Commissioners by the day on which it became due; or (b) he would, but for section 59(1A), be in default in respect of that period for the purposes of section 59”