It seems too much of a coincidence that a George Sidney Parry, born about 1900 in the 1911 census is not the correct one. Here are the details.
Willington Tarporley, Willington, Cheshire,
John Parry Head Married Male Farmer And Miller 41 1870 Tarvin Cheshire
Louisa Parry Wife Married Female - 38 1873 Delamere Cheshire
Hilda May Parry Daughter - Female School 13 1898 Kelsall Cheshire
George Sidney Parry Son - Male School 11 1900 Kelsall Cheshire T
Cyril Charles Parry Son - Male School 10 1901 Kelsall Cheshire
Maud Parry Daughter - Female School 9 1902 Willington Cheshire