If you look at Chris' previous reply and her link to Gloucestershire bdm this question has been answered.

Francis Henry COATES - 1897 Forest of Dean Westbury on Severn Newnham - which gives the mother's maiden name as STERRY

Frederick G COATES - 1900 - Cheltenham
Child surname: COATES
Child Forename: Frederick G
Father's Surname: (BLANK)
Mother's Surname: STERRY
Mother's former name: (BLANK)

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William COATES died in 1901 (in previous reply) - so two children by Gertrude, Francis 1897 and Frederick 1900

For Records

Baptism at Longhope - 28 May 1897

Francis Henry STERRY

father: William

mother: Gertrude

residence: May Hill, Longhope

occupation: Butcher

memoranda: born 20 December 1897

and death on Ancestry - Francis Henry COATES - Forest of Dean 1980 age 83 (with the same birth date - 20 December 1897)