An appeal may be brought against—
If an appeal under subsection (1)(a) above against an amendment of a self-assessment is made while an enquiry is in progress in relation to any matter to which the amendment relates or which is affected by the amendment none of the steps mentioned in section 49A(2)(a) to (c) may be taken in relation to the appeal until a partial closure notice is issued in relation to the matter or, if no such notice is issued, a final closure notice is issued.
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In the case of a simple assessment, the right to appeal under subsection (1)(d) does not apply unless and until the person concerned has—
This section has effect subject to any express provision in the Taxes Acts, including in particular any provision making one kind of assessment conclusive in an appeal against another kind of assessment.