I've found a version by Geoff and Sue Harris, which they say is 'reputedly of Gypsy origin' and they call it the Worthy Wood Carol

Sleep my darling, darling little son,
Sleep my lovely, lovely little one,
For the world is heavy gold
For your little hand to hold
Sleep then!
Sleep my darling, lovely little son

Sleep my darling, darling little son,
Sleep my lovely, lovely little one,
You were come to die for we
All upon the criss-cross tree
Sleep then!
Sleep my darling, lovely little son

Sleep my darling, darling little son,
Sleep my lovely, lovely little one,
For the Dear God, he don't mind
If you finds us too unkind
Sleep then!
Sleep my darling, lovely little son

Sleep my darling, darling little son,
Sleep my lovely, lovely little one,
For the world is heavy gold
For your little hand to hold
Sleep then!
Sleep my darling, lovely little -
Sleep my darling, lovely little -
Sleep my darling, lovely little, lovely little, lovely little son

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Line breaks added,and thread title changed: "add" replaces "req" so harvesters find the song. --JoeClone