Circa 1965 (?). From Dorothy "Dot" Jarlett's collection 

(she was the Lennons' housekeeper/babysitter for quite some time). Edited by me. 

1965, Cyn wrote this postcard to Julian & Dot (the housekeeper) when John & her were away in Austria (the Beatles some scenes for Help! there). 

Note that is it addressed to "Master Julian Lennon" lol.