Frederick James Johnson married Lilly (Elizabeth) Tatt in 1906
Her name was Elizabeth Ann so I don't know why she married under the name of Lilly!

Marriages Dec 1906 (>99%)

Johnson Frederick James Downham 4b 952
TATT Lilly Downham 4b 952


In the 1911 census they are living in Stow Bardolph with their son Ronald

Name: Frederick Johnson
Age in 1911: 33
Estimated Birth Year: abt 1878
Relation to Head: Head
Gender: Male
Birth Place: Stow Bardolph, Norfolk
Civil parish: Stow Bardolph
County/Island: Norfolk
Country: England
Street Address: Barroway Drove Nr Downham Mkt, Downham
Marital Status: Married
Occupation: Farmer
Name Age
Frederick Johnson 33
Elizabeth Johnson 27
Ronald Johnson 1
Walter Well 15

Elizabeth gives Ramsey, Huntingdonshire as her birth place so this looks like her with her family in 1901

National Archive Reference:
RG number: RG13
Piece: 1892
Folio: 99
Page: 40
Reg. District: Downham
Sub District: Wiggenhall
Parish: Stow Bardolph
Enum. District: 6
Ecclesiastical District: Nordelph
City/Municipal Borough:
Address: Rays Farm, Stow Fen, Stow Bardolph
County: Norfolk

Name Relation Condition Sex Age Birth Year Occupation , Disability Where Born
TATT, Henry Head Married M 45 1856 Foreman On Farm
Ramsey, Huntingdonshire
TATT, Mary Wife Married F 45 1856
Whittlesea, Cambridgeshire
TATT, Elizabeth Daughter Single F 18 1883
Ramsey, Huntingdonshire
TATT, Arthur Son Single M 16 1885 Carter On Farm
Ramsey, Huntingdonshire
TATT, Herbert Son M 7 1894 At School
Ramsey, Huntingdonshire
HATTON, Herbert Boarder Single M 23 1878 Horse Keeper On Farm
Stow Bridge, Norfolk
HUBBARD, Henry Boarder Single M 20 1881 Horse Keeper On Farm
Outwell, Norfolk
TIFFIN, Arthur Boarder Single M 23 1878 Carter On Farm
Stow Bardolph, Norfolk

Ronald was born in late 1909
Births Dec 1909 (>99%)
Johnson Ronald Frederick Downham 4b 290

and there was a daughter born in 1912

Births Dec 1912 (>99%)
Johnson Dora M Tatt Downham 4b 556

Ronald may have married in 1932

MarriageFinder: Ronald F Johnson married Gladys Williams
Name: JOHNSON, Ronald F
Registration district: Downham
County: Norfolk
Year of registration: 1932
Quarter of registration: Oct-Nov-Dec
Spouse's last name: Williams
Volume no: 4B
Page no: 901

Name: WILLIAMS, Gladys
Registration district: Downham
County: Norfolk
Year of registration: 1932
Quarter of registration: Oct-Nov-Dec
Spouse's last name: Johnson
Volume no: 4B
Page no: 901

he died in 1979

Civil Registration event: Death


Name: JOHNSON, Ronald Frederick
Registration district: Norwich Outer
County: Norfolk
Year of registration: 1979
Quarter of registration: Oct-Nov-Dec
Date of birth: 19 November 1909
Volume no: 10
Page no: 1933

Frederick James died in 1962

Civil Registration event: Death


Name: JOHNSON, Frederick J
Registration district: Downham
County: Norfolk
Year of registration: 1962
Quarter of registration: Oct-Nov-Dec
Age at death: 84
Volume no: 4B
Page no: 461

Ronald's sister Dora married Ernest S. Rolfe in 1934

I am not related to this family I have just done some research for you.