12. If a disposal on which by virtue of paragraph (2) or (4) of article 8 or paragraph (1) of article 25 no gain was regarded as arising is subsequently regarded as giving rise to a gain by virtue of paragraph (3) or (5) of article 8 or paragraph (2) of article 25 the disposal statement shall give the date of the previous disposal statement in which information about that disposal was given in accordance with paragraph 11 of this Schedule.