15. The powers conferred by article 14 may be exercised by the shadow authority only—
(a)in the discharge of the functions specified or referred to in articles 8 to 11 and 13; and
(b)in the same manner, and subject to the same conditions and limitations, as if it were a non-metropolitan district council; and
(c)where the exercise of the power would involve incurring expenditure or acquiring a liability, where the expenditure or liability relates to a matter which, before 1st April 2019, is the responsibility of one of the Relevant Councils, with the prior consent of that council.