There is a paper label to the reverse of the present relief identifying the figure as St. Aubert, the Bishop of Avranches in Normandy. Although it is unlikely that an English alabaster carver would represent a French Bishop, it is clear that the figure is indeed a Bishop Saint, and so it is remains a possibilty that the present figure could be Aubert.
In 708, Aubert had a vision in which the Archangel Michael appeared to him and instructed him to build a shrine on Mount Tombe (known today as Mont Saint-Michel), a rocky islet off the coast of Normandy, long venerated as a holy place. Aubert at first doubted that this was the word of God, and the Archangel had to visit him on a further two occasions to pursuade him to build the shrine, at one point burning his finger into the saint's skull. The oratory was finally consecrated on 16 October 709. The present Romanesque abbey church was built by William of Volpiano in the 11th century.
The present relief, together with additional panels of standing saints, would have formed a slender rhythmical counterpart to the larger narrative panels on an elaborate altarpiece, such as that in the Hôtel de Ville, Compiègne (Cheetham 1984, op. cit. p. 23, fig. 12). There is, in fact, a Nottingham alabaster altarpiece in the abbey of Mont Saint-Michel, which is thought to come from the nearby church of St. Leger (Cheetham 2003, op. cit. p. 172, no. 14).
F. Cheetham, English Medieval alabasters, with a catalogue of the collection in the Victoria and Albert Museum, Oxford, 1984, p. 23, fig. 12; F. Cheetham, The Alabaster men. Sacred images from Medieval England, exh. cat., Daniel Katz Ltd., London, 2001; F. Cheetham, Alabaster images of Medieval England, Woodbridge, 2003, p. 172, no. 14