The powers of HMRC to enquire into LTRs are based on those for income tax and corporation tax, as are the powers to issue notices for documents and information. HMRC can issue a notice to produce documents for purposes of an enquiry, against which the purchaser can appeal.
The basic rule is that HMRC can make an enquiry into a return within nine months after:
(a)the filing date, if the return was delivered on or before that date;
(b)the date on which the return was delivered, if it was delivered after the filing date;
(c)the date on which an amendment was made (if the return is amended by the purchaser under Sch. 10, para. 6).