1938, based on the cinema listings in a cutout from a newspaper folded in with the pattern pieces (Snow White and the Seven Dwarves was playing at the Melba, children 20 cents all times.)
Independence Day is always a good time to get your Colonial on. There is something sort of uproarious about providing the 9d price in the British Isles. Perhaps if you squint really hard, the instruction sheet says "George III," not "George Washington"
Size 6 is for a little tyke, and won't he look splendid riding on the fire engine in the July 4th parade? That is, if Mama managed to work her way through the tiny instruction sheet and the half inch seam allowances.
Have a safe and happy Independence Day, everybody!