This (last message) seems to be the answer as to why initially I couldn't find William and Violet in the 1911 census. Violet was named at birth and bapt as Isabella, and William was known as John, if this is the right couple, following?

1911 Household transcript:
Name Relation Condition/Yrs married Se x Age BirthYear Occupation Where Born
CORRIN, John Head Married M 33 1878 Farmer Isle of Man Arbory = William John Karran Corrin - (have not found birth or christening record yet)
CORRIN, Isabella Wife Married 8 years F 28 1883 Isle of Man Patrick = Violet Isabel Catherine Kelly (have christening record, looking to prove birth)
CORRIN, Harford Son M 6 1905 Isle of Man Patrick = John Harford Corrin
CORRIN, Hartwell Son M 1 1910 Isle of Man Patrick = Richard Hartwell Corrin
CORRIN, Annie Daughter F 7 1904 Isle of Man Patrick = Annie Elizabeth Corrin
CORRIN, Eunice Daughter F 4 1907 Isle of Man Patrick = Eunice I(sabel?) Corrin
CORRIN, Edna Daughter F 3 1908 Isle of Man Patrick = Alice Edna Corrin
DAVIS, Thomas Servant Single M 18 1893 Horseman On Farm Isle of Man Malew DAVIS, Thomas Servant Single M 16 1895 Cowmanman On Farm Isle of Man Onchan

There may also be one more male Corrin born to William & Violet
Have not looked for birth or christening records for children yet.

Tim