65.—(1) Subject to paragraphs (2) and (4), if at any time between the making of a claim and its determination, or during the benefit period, there is a change of circumstances which the claimant or any person by whom or on whose behalf sums payable by way of council tax benefit are receivable might reasonably be expected to know might affect the claimant’s right to, the amount of, or the receipt of council tax benefit, that person shall be under a duty to notify that change of circumstances by giving notice in writing to the designated office.
(2) The duty imposed on a person by paragraph (1) does not extend to notifying changes—
(a)in the amount of a council tax payable to the appropriate authority;
(b)in the age of the claimant or that of any member of his family;
(c)in these Regulations; or
(d)in the case of a claimant on income support, any changes in circumstances which affect the amount of income support but not the amount of council tax benefit to which he is entitled, other than the cessation of that entitlement to income support.
(3) Notwithstanding paragraph (2)(b) or (d) a claimant shall be required by paragraph (1) to notify the designated office of any change in the composition of his family arising from the fact that a person who was a member of his family is now no longer such a person because he ceases to be a child or young person.
(4) Where the amount of a claimant’s council tax benefit is the alternative maximum council tax benefit in his case, the claimant shall be under a duty to give written notice to the designated office of changes which occur in the number of adults in the dwelling or in their total gross incomes which might reasonably be expected to change his entitlement to that council tax benefit and where any such adult ceases to be in receipt of income support the date when this occurs.