(3)Where within a period of seven years two warnings have been given to an insurer under sub-section (2) and they have been disregarded by hi m, theAuthority may cause an investigation and valuation, as at such date as theAuthority may . specify, to be made at the expense of the insurer by an actuary appointed by the insurer for this purpose and approved by theAuthority, and the insurer shall place at the disposal of the said actuary all the materials required by hi m for the purpose of such investigation and valuation, within such period, not being less than three months, as theAuthority may specify.