John E Bowen also lived in the New North Road cottage during 1939. He made nautical and aeronautical items. There was a Hainault company specialising in this type of work. They were originally clockmakers that began making sextants and chronometers for ships in the River Thames. Their factory produced marine and aircraft instrumentation including sonar. This company would later become 'Kelvin Hughes'. Similar work was done by Plessey, a firm that took over a three-mile stretch of tunnel from Gants Hill to Leytonstone during World War II, converting it into a factory to make aircraft components. The tunnel gave protection against air raids to ensure that the production line was not hindered when bombs fell, and would later became part of the Central Line Underground.