Enquiries into Tax Returns: enquiry procedures
Amendment of return by taxpayer during enquiry
An officer can extend his or her existing enquiry into a tax return to include any amendment made by the taxpayer during the enquiry (S9B(2)). Normally the officer will enquire into the tax return, as it was when the enquiry was opened, and into any amendments made during the enquiry.
Power to call for information for purposes of enquiries
Guidance on information powers is in the Compliance Handbook at CH23000+.