I think your best route at this point is going to be via DNA or a "duplicate" birth cert ?

Child Surname Child Forename Mother's Former Name Year District Office Register Entry

SMITH Frederick Dennis 1925 Forest of Dean Monmouth, West Dean 8 93
SMITH Frederick Dennis 1925 Forest of Dean Westbury on Severn, East Dean 31 344

Year: 1927
Month: Apr
Day: 18
Grooms_Surname: NICHOLLS
Grooms_Forenames: Sidney John
Grooms_Age: 26
Groom_Condition: Bachelor
Grooms_Occupation: Collier
Grooms_Residence: The Scowles Coleford
Grooms_Fathers_Surname: NICHOLLS
Grooms_Fathers_Forenames: Albert John
Grooms_Fathers_Occupation: Labourer
Brides_Surname: SMITH
Brides_Forenames: Caroline Edith
Brides_Age: 20
Brides_Condition: Spinster
Brides_Occupation:
Brides_Residence: Whitecliff Coleford
Brides_Fathers_Surname: SMITH
Brides_Fathers_Forenames: Walter
Brides_Fathers_Occupation: Collier
Licence_or_Banns: Banns
Date_of_Banns:
Signature_or_Mark: Both sign
Witness_1: Walter Smith
Witness_2: M A Nicholl
Other_Witnesses: Elizabeth Smith
Officiating_Minister: Edward H Brice
Event: Marriage
Memoranda:
Notes:
Register_Reference: P93/1 IN 1/13
Page_Number: 92
Parish_Chapel: Coleford

1939 Scowles Rd. Coleford
Sidney J Nicholls 06 Apr 1901 Male Colliery Hewer Married 85 1
Caroline E Nicholls 17 Sep 1907 Female Incapacitated Married 85 2
Frederick O Nicholls 22 Apr 1925 Male General Labourer Single 85 3
Albert S I Nicholls 03 Sep 1927 Male At School Single 85 4
Charles W Nicholls 24 Dec 1929 Male At School Single 85 5
Robert H Nicholls 04 Feb 1932 Male At School Single 85 6

First name(s) Rhoda
Register number B61
Last name Sidaway
Entry number 217
Sex Female
Date of registration mm/yy 0401
Birth day 30
County Staffordshire
Birth month 4
Country England
Birth year 1919
Record set England & Wales Deaths 1837-2007
Death quarter 2
Category Birth, Marriage, Death & Parish Records
Death year 2001
Subcategory Civil Deaths & Burials
District Sandwell
Collections from Great Britain, England

Marriages Jun 1942 (>99%)
Sidaway John T Smith F.of Dean 6a 950
Smith Rhoda Sidaway F.of Dean 6a 950

Possible Children depending where they lived

Sidaway Angela Smith Smethwick 6b 1445
Sidaway Pauline R M Smith Pontypridd 11a 766
Births Sep 1945 (>99%)

Sidaway Stephan J Smith Smethwick 6b 1242
Births Dec 1946 (>99%)

Sidaway Pamela Smith Smethwick 9b 693
Births Mar 1950 (>99%)

Sidaway Derek J Smith Oldbury 9d 218
Births Dec 1952 (>99%)

SIDAWAY Margaret A SMITH Oldbury 9d 215
Births Dec 1960 (>99%)

SIDAWAY Stephen C SMITH Rowley R. 9b 442
Births Jun 1966 (>99%)

1939 Rosewarne, Coleford,
Samuel McGovern Morrison 16 Oct 1898 Male Medical Doctor Married 92 1
Dorothea M Morrison 10 Nov 1900 Female Domestic Duties Married 92 2
Peter F Morrison 23 Nov 1927 Male At School Single 92 3
The record for this person is officially closed.
The record for this person is officially closed.
The record for this person is officially closed.
Rhoda Sidaway (Smith) 30 Apr 1919 Female Domestic Servant Single 92 7
Kathleen A Morgan,Buffer 28 Jul 1921 Female Domestic Servant Single 92 8

1921
Rhoda with Walter etc in East Dean

1911 Ruspidge
Walter Smith Head Married Male 34 1877 Roadman below ground East Dean Glos
Rhoda Smith Wife Married Female 29 1882 - East Dean Glos
William E Brown Son - Male 13 1898 School East Dean Glos
May Smith Daughter - Female 10 1901 School East Dean Glos
Elizabeth Smith Daughter - Female 7 1904 - East Dean Glos
Eva A Smith Daughter - Female 6 1905 - East Dean Glos
Joseph H J Smith Son - Male 4 1907 - East Dean Glos
Caroline E Smith Daughter - Female 3 1908 - East Dean Glos
Dorothy Smith Daughter - Female 0 1911 - East Dean Glos

1901 Ruspidge
Mark Smith Head Married Male 50 1851 Coal miner roadman below ground East Dean, Gloucestershire, England
Caroline Smith Wife Married Female 49 1852 - East Dean, Gloucestershire, England
Walter Smith Son Married Male 24 1877 Coal miner hewer below ground East Dean, Gloucestershire, England
Emma Smith Daughter Single Female 17 1884 - East Dean, Gloucestershire, England
Agnes Smith Daughter Single Female 10 1891 - East Dean, Gloucestershire, England
Edith Smith Daughter Single Female 6 1895 - East Dean, Gloucestershire, England

Hi, sorry I haven’t been on here for awhile, and my information isn’t going to be of any help really but I am the granddaughter of Albert Sydney John and Agnes Nicholls. (They adopted me and brought me up so I class them as my
Mother and farther)I remember Uncle fred very well, I also remember his children who were a lot older than myself, I remember being told as I got older that Fred never had the same farther but unfortunately wasn’t told who his farther was. Sorry I am unable to help you with this information, good luck in your search, my son was speaking to someone earlier originally from Coleford who are from the Smith family, I have also come to look for information on the Smith family to see if we are related to the Same family my son spoke to earlier,