There are two Walter Gale entries in the IoM in the 1911 census, b.1888 & 1889, born in Port St Mary and in Rushen, but they are not with their families.
His marriage cert should show how long he had been in Australia.
What was his wife's name, and where was he living?

Here is the Rushen one in 1901:

Name Relation Condition Se x Age Birth Year Occupation Disability Where Born Original
census image

GALE, Thomas Head Married M 41 1860 Fireman On Steamship Rushen Isle of Man VIEW
GALE, Margaret Wife Married F 40 1861 Andreas Isle of Man VIEW
GALE, Walter Son Single M 14 1887 Butchers Apprentice Rushen Isle of Man VIEW
GALE, William Son Single M 12 1889 Rushen Isle of Man VIEW
GALE, James H Son Single M 11 1890 Rushen Isle of Man VIEW
GALE, John R Son Single M 2 1899 Douglas Isle of Man VIEW
PIERCY, Amelia Step Daughter Single F 12 1889 England VIEW

RG number:
RG13 Piece:
5305 Folio:
46 Page:
8

Registration District:
Isle of Man Sub District:
EnumerationDistrict:
3 Ecclesiastical Parish:
St Barnabas

Civil Parish:
Onchan Municipal Borough:
Address:
1, King Street, Onchan, Douglas County:
Isle of Man

Where does the KEIG name fit in? Not sure what you mean by that discovery. Where did he find that this was his name?

Sue