7(1)The Inland Revenue may enquire into a self-certificate if they give notice of their intention to do so (“notice of enquiry”)—U.K.
(a)to the purchaser,
(b)before the end of the enquiry period.
(2)The enquiry period is the period of nine months after the date on which the self-certificate was produced.
(3)A self-certificate that has been the subject of one notice of enquiry may not be the subject of another.