15(1)This paragraph applies if a person is required to make and deliver a return under this Schedule in respect of a disposal and, at any time after the completion of the disposal—
(a)it becomes reasonable to expect that, by reference to the person’s residence, a provision of TCGA 1992 will apply,
(b)it becomes reasonable to conclude that a provision of TCGA 1992 conferring a relief applies in relation to the disposal,
(c)matters relevant to the application of section 1I of TCGA 1992 become known, or it becomes reasonable to make a different estimate of those matters, where an estimate of those matters was used in the return, or
(d)the value of anything, or of any amount to be apportioned to anything, becomes known where an estimate was used in the return.
(2)The person may (but need not) assume, for the purposes of this Schedule—
(a)that there is an additional disposal to which this Schedule applies,
(b)that the additional disposal completed at the later time by reference to which this paragraph applies, and
(c)that the additional disposal is in all other respects a replication of the actual disposal.
(3)In determining the amount of capital gains tax notionally chargeable as at the filing date for a return in respect of the additional disposal, the actual disposal is ignored.