Where an assignment of a registered layout-design is made otherwise than in connection with the goodwill of business in which such layout-design has been or is used, the assignment shall not take effect unless the assignee, not later than the expiration of six months from the date on which the assignment is made or within such extended period, if any, not exceeding three months in the aggregate, as the Registrar may allow, apply to the Registrar for directions with respect to the advertisement of the assignment, and advertises it in such form and manner and within such period as the Registrar may direct.