Classic song, written in 1936 by Sammy Cahn, Saul Chaplin, L E Freeman, Mann Holiner and Alberta Nichols.
Recorded by many artists: Billie Holiday, Fats Waller, The Ink Spots, Ella Fitzgeraöld etc.
https://en.wikipedia.org/wiki/Until_the_Real_Thing_Comes_Along
Sandy Denny's best recording of this song is the BBC Session version with Bob Harris from Nov 14, 1973.
It's available on Disc 2 of the re-issue of Sandy Denny's "Like an old-fashioned waltz" (2012)
Also in the "A boxful of treasures" Sanny Denny box (2004).
Like many jazz standards, it originally had a slow 12 bar intro section, often ignored.
Sandy dosen't sing it, so it's also omitted here.
[Verse 1]
Bb
I'd work for you
F7+5 Bb
I'd slave for you
Bb/A Bb/Ab G9 Dm7 G7
I'd be a beggar or a knave for you
Cm7 F7 Bb
If that isn't love, it will have to do
Bbdim Cm7 Ebm6 F7
Until the real thing comes along
[Verse 2]
Bb
I'd gladly move
F7+5 Bb
The earth for you
Bb/A Bb/Ab G9 Dm7 G7
To prove my love, dear And its worth for you
Cm7 F7 Bb
If that isn't love, it will have to do
Eb6 Gm6 A7 D
Until the real thing comes along.
[Middle 8]
Adim Em7 A7 D
With all the words, dear, at my command
Abdim Em7 A9 D
I just can't make you understand
Ebdim Em7 A7 D
I'll always love you, darling, come what may
Bdim
My heart is yours
F7 Abdim F7
What more can I say?
[Verse 3]
Bb
I'd sigh for you
F7+5 Bb
I'd cry for you
Bb/A Bb/Ab G9 Dm7 G7
I'd tear the stars down from the sky for you
Cm7 F7 Bb
If that isn't love, it will have to do
Eb6 Bb
Until the real thing comes along.
Note: Take the Bb at the end of line 2 of the verse as barré on the 6th fret.
Then just walk the bass notes A - Ab down to the G9 chord.
(There's no need to play full Bb/A Bb/Ab chords, just do the little walking base line.)