Initially with Smiths Industries and later at Ultra Electronics, Allan worked mainly in aviation and in particular on the control systems for Concorde.
He left Ultras to start his own Research and Development company Seaco in 1966. Among other things, Saeco invented Skilock to rescue skiers lost under avalanches, the first digital clock and an alarm for electrical malfunction in cars.
Allan also started Dynalarm and the firm developed and marketed building alarms.