Though the Holst version is shown in most carol books including The Oxford Book of Carols (1928, no. 187, titled "Mid-Winter") and hymnals (The English Hymnal; Hymns Ancient and Modern), Harold Darke's composition has been recorded on many CDs (9 in front of me). Both scores are in The New Oxford Book of Carols (1992, no. 111), its Shorter edition (no. 63), and 100 Carols for Choirs (Oxford, nos. 39 & 40). There's one more, composed by William Llewellyn, in The Novello Book of Carols, part 1 (1986, no. 29); it's on Worcester Cathedral Choir's Joy to the World CD.