4 Where on or after 9th June 1988 but before 23rd June 1988 an application is made for an extension of the period of copyright in any registered design in respect of which the period of copyright is due to expire on or after 23rd June 1988, the fee payable on such application shall be that which would be payable if the application were made on or after 23rd June 1988 and rules 1(2) and 3 above had come into operation.