53(1)An officer of Revenue and Customs may enquire into a claim if, within the time allowed, the officer gives notice to the claimant of the officer's intention to do so.
(2)The time allowed is the period ending with the quarter day next following the first anniversary of the day on which the claim was made.
(3)The quarter days are 31 January, 30 April, 31 July and 31 October.
(4)A claim enquired into under sub-paragraph (1) may not be the subject of a further notice under that sub-paragraph.
(5)An enquiry is completed when the officer by notice (a “closure notice”) informs the claimant that the enquiry is complete and states the conclusion reached in the enquiry.
(6)The conclusion must be one of the following—
(a)that no amendment of the claim is required, or
(b)that the amendments of the claim specified in the notice are to be made.
(7)A closure notice takes effect when it is issued.
(8)The officer must give effect to any amendments made by the closure notice by making such adjustments as may be necessary whether—
(a)by way of assessment, or
(b)by discharge or repayment of tax.
(9)The adjustments must be made within 30 days of the date of issue of the closure notice.
(10)Paragraph 23 (direction to complete enquiry) applies in relation to an enquiry under this paragraph as it applies in relation to an enquiry under paragraph 16.