hi. not spotted him as that name on the 1911 index on ancestry, certainly not in birmingham birn 1907, there's an Oliver Hindmarch born @1902 on the 1911 living in yorkshire though born worcester
1911 England Census 1911 England Census
Name: Oliver Hindmarsh
Age in 1911: 9
Estimated Birth Year: abt 1902
Relation to Head: Son
Gender: Male
Birth Place: Netherton, Worcester, England
Civil parish: Royston
County/Island: Yorkshire-West Riding
Country: England
Street Address: Whincover Royston Barnsly Yorks
Marital Status: Single
Occupation: School
Registration district: Barnsley
Registration District Number: 507
Sub-registration district: Darton
ED, institution, or vessel: 05
Piece: 27549
Household Members: Name Age
James Hindmarsh 33
Hannah Hindmarsh 35
Oliver Hindmarsh 9
James Hindmarsh 5
Cornelius Hindmarsh 3
Gladys Hindmarsh 1
Wellie Hindmarsh Under 1/12
Source Citation: Class: RG14; Piece: 27549; ; .
I'll just look at the original to see if there is a transcription error on the age