Where any instrument under which the governing body of an aided or special agreement school is constituted was in force immediately before the commencement of this Act by virtue of paragraph 1 of Schedule 5 to the M1Education (No. 2) Act 1986, the instrument shall have effect thereafter as if made by order under section 76 of this Act; but this paragraph shall cease to apply to any such school if it is grouped with any other school or schools under section 89 of this Act.