Later children were born outside London:
1904 (Dec qtr): Albert James, born in Bristol.
1907 (Jun qtr): Cyril Edward, born in Keynsham, buried (Commonweath War Grave) in Sydney in 1946.
1908 (Dec qtr): Olive May, born in Bristol.
Free 1911 index suggests the family had moved to Hampshire, but Sidney may not have been with them.