Fair Ellen of Radcliffe is in several of the Victorian anthologies of Lancashire verse including the daddy of them all, 'Ballads and Songs of Lancashire' by Harland and Wilkinson. It's the version that Tim van Eyken uses—whether from there or reprinted elsewhere. Here's what Harland and Wilkinson had to say about the ballad (Third Edition 1882):

THE RADCLIFFE TRAGEDY OF "FAIR ELLEN."

Amongst the common people in the neighbourhood of Radcliffe and Bury, a story is currently believed that the kitchen of Radcliffe Tower was the scene of a cruel tragedy, perpetrated by a menial on the daughter of the lord, to gratify the malice and cupidity of a stepmother; and a red stain on the floor marked, as it is said, the place where the victim fixed her bloody hand while her murderer perpetrated the atrocity. Although there is nothing in the family history of the Radcliffes to support this tradition, and although for 100 years back, at least, there has been no such relic to be found in Radcliffe Tower, the tradition is not on that account the less firmly believed. A ballad of the murder, under the title of "The Lady Isabella's Tragedy," is printed in Bishop Percy's Reliques, with the following introduction:—"This ballad is given from an old black-letter copy, in the Pepys collection collated with another in the British Museum (H. 263, fol.) It is there entitled 'The Lady Isabella's Tragedy, or the Stepmother's Cruelty; being a relation of a lamentable and cruel murther, committed on the body of the Lady Isabella, the only daughter to a noble Duke,' etc. To the tune of 'The Lady's Fall.' To some copies are annexed eight more modern stanzas, entitled, 'The Duchess's and Cook's Lamentation.'" The legend runs somewhat thus:—"In times long past, Sir William de Radcliffe possessed Radcliffe Tower. His first wife had died in giving birth to her first child, a girl, who, when she grew up, became remarkable for her beauty. But, in the meantime, Sir William had married again, and the stepmother, a haughty and ambitious woman, cordially hated the only person who divided her husband's affections with herself. One day, when Ellen was about eighteen years of age, Sir William went out hunting. This seemed to the stepmother a good opportunity for the execution of a nefarious design she had long cherished. Calling her daughter to her, she said, 'Fair daughter, go, I beseech thee, and tell the master-cook that he must dress the white doe for dinner.' The damsel, unconscious of any harm, did as she was requested. When she had delivered her message the cook said, 'You are the white doe my lady means; and it is you I must kill.' In vain did the unhappy victim implore and intreat, and in vain did a scullion boy offer himself in her place; the damsel was killed, and made into a pie. In the meantime, Sir William's chase had been long and animated; but he was unable to drive away a foreboding of ill that kept crossing his mind, and at last he felt impelled to order his retinue to return. At dinner he called for his daughter to carve for him, as was her wont, but she appeared not. On asking his wife where she was, she urged as an excuse that she was gone into a nunnery, but the scullion boy exclaimed, ''Tis false; cut open that pie and there you will find your daughter!' He then related the sad catastrophe, and the cruel stepmother was condemned to be burned at the stake, and the cook to stand in boiling lead. The scullion boy was declared the heir of all his lord's possessions."

Dr. Whitaker, in his History of Whalley, says:—

"To this place and family (Radcliffe of Radcliffe Tower) are attached the tradition and ballad given by Dr. Percy under the name of 'Isabella,' but here applied to a Lord Thomas and Fair Ellenor, father and daughter, whose figures are supposed to be graven on a slab in the church, [This slab Dr. Whitaker describes as "an alabaster slab, north-west of the altar in Radcliffe church, covering the remains of James de Radcliffe, founder of the church. There are, as usual, a male and female figure cumbent, the man in armour, and some remains of children in praying attitudes, beneath. What can be recovered of the inscription round the verge is as follows:—Orate pr. aia Jacobi de Radclyff . . . qu ai . . . propicieret Deus." That is, "Pray for the souls of James de Radcliffe, etc., on whose souls God have mercy."] which the common people—concluding, I suppose, from its whiteness that it was meant as an emblem of the innocence it is said to cover—have mutilated, by breaking off small fragments as amulets for the prevention or cure of disorders. Traditions, always erroneous in their circumstances, are yet rarely devoid of foundation; and though the pedigrees of Radcliffe exhibit no failure of the family by the premature death of an heiress; though the last Richard de Radcliffe, who had daughters only, [He died in 1502, as per inquisition, aged 31, leaving daughters, who are not noticed in the descent.] certainly did not make 'a scullion boy the heir of all his land,' when he settled it on Radcliffe, Baron Fitzwalter; though the blood actually pointed out on the kitchen floor, where this Thyestasan banquet is said to have been prepared, deserves no more regard than many of the stories and appearances of the same kind; yet . . . we are not to discard as incredible the tradition of a barbarous age, merely because it asserts the sacrifice of a young and beautiful heiress to the jealousy or the avarice of a stepmother. When this is granted, the story of the pie, with all its horrors, may safely be ascribed to the inventive genius of a minstrel. On the whole, Radcliffe is a place which, not only from its antiquity and splendour, but from the great families which have branched out from it, and the romantic tradition attached to it, can scarcely be surveyed without enthusiasm, or quitted without regret." Both Radcliffe Tower, and the Hall, have long since been demolished. The ballad is printed both by Roby and Baines; the latter observing that the story is curious, and deserves to be preserved in its original garb, as well for its antiquity as for its poetic merit.