- Welcome to Seaforth Manufacturing CO. PTY. LTD. Sydney Australia Seaforth Venetians Cedar Venetians & Security Systems Manufacturers and Exporters of the Finest Venetian Blind Slats Seaforth Venetians manufacture quality made to measure venetian blinds for interior and exterior applications. Made of durable Canadian Cedar the blinds provide the beauty of natural timber with the versatility of ...www.seaforth.com.au