In all the circumstances Edith Margaret Whitehead (mmn Mitchell) born I think on 21 Sep 1916 in Fulham looks a more likely contender.
Apart from anything else she is a good geographical match with the 1933 Kensington birth and Fulham foster mother.
Would that be the Edith that married Ernest Ball in 1934?
Edith Margaret Ball born
21 Sep 1916Date of Registration: Dec 1994
Age at Death: 78
Registration district: Merton
Inferred County: Surrey
Register Number: B32
District and Subdistrict: 2441
Entry Number: 180
Ernest Samuel Ball born 10 Nov 1908
Date of Registration: Jan 1984
Age at Death: 75
Registration district: Fulham
Inferred County: London
Volume: 12
Page: 818
1938/39 Fulham London Electoral Register
Ernest Samuel Ball &
Edith Margaret Ball living at 28 Kingswood Road SW6
1934 Fulham address 1 Lodge Avenue SW6
Ernest Samuel Ball
also at same address
C E Mitchell
E M & H E Oliver A M & F J WhiteheadHave not given full names of others as I don't know yet if they are deceased
ADDEDFrederick Joseph Whitehead of 78 Robert Owen House Fulham died 15 Feb 1951 Admin 29 March to widow
Alice Minnie (she died 1967)
They married 25 Dec 1915 St John, Walham Green,
his father Charles Whitehead,
her father Charles Edward Mitchell
Edith Margaret Mitchell (she died 1958) her father Charles Edward Mitchell
married H E Oliver 25 Dec 1921