You might think of Marjory Kennedy-Fraser as just a folksong collector and editor (link will open a new tab to the Wikipedia article). With Gaelic poet and scholar Kenneth MacLeod, she was responsible for the collection and publication of four volumes of Songs of the Hebrides (the craggy islands north west of Scotland) in the first quarter of the 20th Century.
But to the tunes (for which she or MacLeod provided English translations, while also displaying in the score the original Gaelic words), she added piano accompaniments of her own making (a few were composed by Granville Bantock), that are no mere hack work. Some are even wonderfully inventive. So if Britten is recognized as the composer of his collections of Folksongs, and even Tippett is credited as the composer of his “Purcell-realizations” (which, as the title says, are no more than realizations of Purcell’s figured bass), then there is no reason why Kennedy-Fraser shouldn’t be recognized as the composer of those Hebridean folksongs.
The piano part is often performed at the harp, as on the recital of soprano Alison Pearce and harpist Susan Drake on Hyperion, “Songs of the Hebrides”, which is an entirely legitimate choice, considereing the “bardic” mythology of the British Isles and the tradition of harpists still very much alive when Kennedy-Fraser was doing her collecting. In fact here own daughter, Patuffa recorded a few of those songs in her own arrangements for Celtic harp (or “clarsach”), and she was very… instrumental in the revival of the instrument. See the review for the links.