8. Where an arrangement was made by the MHAC before the appointed day for an authorised person to investigate any complaint under subsection (1)(b) of section 120 of the 1983 Act but the steps pursuant to that arrangement have not been completed before the appointed day that arrangement shall, on and after the appointed day, be treated as though it were made by the regulatory authority under subsection (4) of section 120 of the 1983 Act (as substituted by paragraph 8 of Schedule 3 to the Act).