" Payments on account (2010/11) "
"(3) In any case where the person -- (a) gave the notice required by section 7 of this Act [see below] within six months from the end of the year of assessment, but (b) was not given notice under section 8 or 8A of this Act until after the 31st October next following that year, the difference shall be payable at the end of the period of three months beginning with the day on which the notice under section 8 or 8A was given. “(4) In any other case that difference shall be payable on or before 31 January next following the year of assessment."