Probably by asking the manufacturer, but if he's no longer in business you might at least find earliest possible date from a history of the company or from a dealer.
Stanley Seymour has written: 'London - day by day' -- subject(s): London City Mission
Stanley Irving was born in 1908, in London, England, UK.
Stanley Beard died in 2007, in London, England, UK.
Stanley Meadows was born in 1928, in London, England, UK.
Stanley Caine was born in 1935, in Southwark, London, England, UK.
Stanley Haynes died in 1958, in London, England, UK of suicide.
Stanley Lemin was born on June 5, 1898, in London, England, UK.
Stanley Lupino was born on May 15, 1893, in London, England, UK.
Stanley Dark was born on May 15, 1874, in London, England, UK.
Stanley Turnbull died on May 8, 1924, in London, England, UK.
Victor Stanley died on January 29, 1939, in London, England, UK.
Stanley Pavey was born on December 23, 1913, in London, England, UK.