A partnership return (including anything included in the return by virtue of section 12ABZB(7)(b) (amendment of partnership return following referral to tribunal)) may be amended by the partner who made and delivered the return, or his successor, by notice to an officer of the Board.
An amendment may not be made more than twelve months after the filing date.
Where a partnership return is amended under this section, the officer shall by notice to each of the partners amend—
the partner's return under section 8 or 8A of this Act, or
the partner's company tax return,
so as to give effect to the amendment of the partnership return.
In this section "the filing date" means—
in the case of a partnership which includes one or more individuals, in respect of a return for a year of assessment (Year 1)—
31st January of Year 2, or
if the notice under section 12AA is given after 31st October of Year 2, the last day of the period of three months beginning with the date of the notice, and
in the case of a partnership which includes one or more companies, the end of the period specified in section 12AA(5B) or (5C).