There is only one entry for Ellen Casement in the 1841 and 1851 census
1841, Andreas, district 5, page 1, Balla Collison
John Quayle, 60, tailor
Catharine, 50
Thomas, 15
Sarah, 9
Ellen Casement 3

1851, Ramsey, district 3, entry 70, Quay
Mary Bryden. head, wiow, 65, charwoman, Lezayre
Ellen Casement, niece, unmarried, 13, scholar, Andreas