Hello you might like to look and read my post about a Smiths Cockpit clock, i was told some time ago the "MA" in the name is for MOTOR ACCESSORIES , also as above used in high end cars, Rolls, Bentleys, could have been late 1930s, maybe late 40s early 50s, my thoughts are late 30s to me what also gives in away are the Roman numerals, the mounting screws at the back is a typical car clock fitting in vintage cars