46.—(1) Where the Board is of the opinion that, in the particular circumstances of an appeal, it is appropriate in the interests of justice to request a party or other person who has made submissions or observations to the Board in relation to the appeal to make submissions or observations in relation to any matter which has arisen in relation to the appeal, it may, in its discretion, notwithstanding section 41(3), 44(4), 45(4) or 50(4), serve on the party or person a notice—

(a) requesting the party or person, within a period specified in the notice F27[(being not less than 30 days beginning on the date of service of the notice)] to submit to the Board submissions or observations in relation to the matter, and

(b) stating that, if submissions or observations are not received before the expiration of the specified period, the Board will, after the expiration of that period and without further notice to the person, pursuant to section 48, determine the appeal.

(2) A party or other person shall not be entitled to elaborate in writing on submissions or observations made in response to a request under subsection (1) or make further submissions or observations in writing in relation to the matter concerned, and any such elaboration, or further submissions or observations shall not be considered by the Board.