You are right, Sue.

Isabella and Daniel are not with the family in the 1851 Census,

1851 Census Lezayre, Close e Volley
Thomas Faragher Head 69 abt 1782 Male Lezayre, Isle of Man, Isle of Man
Isabella Faragher Wife 56 abt 1795 Female Ballaugh, Isle of Man, Isle of Man
Robert Faragher Son 22 abt 1829 Male Lezayre, Isle of Man, Isle of Man
William Faragher Son 16 abt 1835 Male Lezayre, Isle of Man, Isle of Man
Catharine Faragher Servant 13 abt 1838 Female Andreas, Isle of Man, Isle of Man

This could be Isabella in the 1851 Census at the home of Joseph Maxwell.

1851 Census Conchan
Castle Lawn, Clarence Terrace.

Isabella Fargher Servant U 24 House Servant Isle of Man