Not a comment on her death but I found the following in British History Online - Sculcoates Parish.
The first demesne Lord of Sculcoates, seems to hav been Benet de Sculcoates, who held it late in the 12th Century. By 1221 the manor had passed to Robert de Grey, Benet’s nephew by marriage. Sculcoates remained in the hands of the Greys until late in the 14th century. They at first held 12 bovates of the Archbishop of York and by 1294 they had acquired the remained 4 bovates.
This same land was recorded in the Inquisition Post Mortem of her great grandson, John Grey, dated 20 October 1311: York - Inquisition taken at Kyngeston upon Hull on Sunday after St. Martin, 5 Edw. II. Scolcotes. A capital messuage, 12 bovates land, and the advowson of the church, jointly held by the said John with Margaret, his wife, to them and to the heirs of the said John, of the Archbishop of York by homage only; and 4 bovates land jointly held, as above, of the heir of Godfrey de Melsa, who is in the king’s wardship, by homage, and service of 4d. yearly for wapentake fines. John, his son, aged 10 and more, is his next heir.
If her husband was the nephew by marriage of Benet de Sculcoates, that would mean she was the daughter of a sibling of Benet, probably a brother.
I cannot find where her given name is shown except in Wikitree with no sources. Wikitree also shows her as the daughter of Guillaume (Senlis) de St Liz.of Huntingdonshire who does not seem to have anything to do with this Sculcoates family.