38Appeals
(1)An appeal may be brought against—
(a)a decision under section 14(1), 15(1), 16(1), 19(3) or 20(1) or (4) or regulations under section 21,
(b)the relevant section 18 decision in relation to a person or persons and a tax credit for a tax year and any revision of that decision under that section,
(c)a determination of a penalty under paragraph 1 of Schedule 2, and
(d)a decision under section 37(1).
(2)“The relevant section 18 decision” means—
(a)in a case in which a decision must be made under subsection (6) of section 18 in relation to the person or persons and the tax credit for the tax year, that decision, and
(b)in any other case, the decision under subsection (1) of that section in relation to the person or persons and the tax credit for the tax year.