Before an application for a conditional use may be heard by the Board of Zoning and Appeals a complete and accurate list of the names and addresses of the owners of all the lands within a radius of 200 feet of the property affected by such application as appears on the latest completed assessment roll of the County of Nassau shall be submitted simultaneously with the application. The applicant shall send, by registered mail, to each owner shown on said list, not less than 10, nor more than 20 days before the date set for a hearing upon this application, a notice addressed to such owners generally, signed by the applicant, identifying the property affected thereby, and setting forth the use requested, and the date, hour and place fixed by the Board of Zoning and Appeals for the hearing thereon. Before such case may be heard by the Board of Zoning and Appeals the applicant must file with the Clerk of the Board not later than five days prior to the hearing date an affidavit of the mailing of such notice as herein provided; said affidavit to be made on forms to be provided by the Board of Zoning and Appeals. This provision shall likewise apply to any application for the extension of a temporary conditional use.