Chapter 4 of Part 41A of the Principal Act is amended -

(a) in section 959R(5)(a) by substituting "such indicative tax calculation as may be provided by the electronic system" for "an indicative tax calculation provided by the electronic system",

(b) in section 959S by inserting the following after subsection (3):

"(4) Where the chargeable person is assessed to tax under section 1023 or 1031H, and his or her spouse or civil partner, as the case may be, is also a chargeable person, then, in relation to the return concerned, no self assessment shall be made under subsection (2) until such time as the spouse or civil partner, as the case may be, has delivered his or her return for the year of assessment.",

and

(c) in section 959V -

(i) by inserting the following after subsection (2):

"(2A) A return and self assessment may be amended under this section only where such an amendment -

(a) arises from an allowance, credit, deduction or relief due under the Acts,

(b) is necessary to correct either an error or a mistake, or