The Beatles - thank you girl live, 1963

"The writing of “Thank You Girl” can easily be narrowed down to February of 1963 during their British nationwide tour with Helen Shapiro. Since February 11th, 1963 was the date for recording of their first British album “Please Please Me,” and the song did not appear on that album, it obviously didn’t exist yet since they would have premiered the song on that day if it had. And since Lennon later confirmed in 1980, as detailed in David Sheff's book "All We Are Saying," that the song “was one of our efforts at writing a single that didn’t work,” it had to have been written before February 28th, 1963, since this was the confirmed date when their next single “From Me To You” was written. Since “Thank You Girl” ended up as the b-side to that British single, it had to have been written sometime between February 11th and 28th of 1963, using the working title "Thank You Little Girl."