I'm at a lost when it comes to tracing the parents of Ellen Robinson, born abt 1850.
All I know about her is that she married John Richmond in 1868. On the marriage record, she is listed as 17 years old, and living in Navigation Street, Birmingham. Her father is listed as being George Robinson, a labourer. One of the witnesses of the marriage was Mary Robinson.
I've been taking a look at the above this afternoon and wondered if witness
Mary Robinson is related to Ellen
might be a sister or mother There's this 1861 census entry it may have no connection to your Robinson family but thought I'd post as her father is named George and his occupation labourer. This Ellen Robinson is not on the 1871 census with her parents George & Mary
BUT if she's only aged 7 that would make only 14 on the 1868 marriage to John Richmond
if incorrect at least this Ellen can be ruled outEllen’s age transcribed as
27 on Anc*y looking at the original entry age written as
29 crossed out and I think it looks as if
7 is written above.
1861c Piece 2139 Folio 80 Page number 13
address
Communication Row Geo Robinson 45 Head London
occ labourer / day
Mary Robinson 29 Wife
Dudley WorcestershireELLEN Robinson 27 Daughter
Sarah Jane Robinson 3 Daughter
Mary Robinson 1/12 Daughter
all others born Birmingham, Plus one boarder
1861c https://www.familysearch.org/ark:/61903/1:1:M7JG-F34?lang=en - family search
Ellen’s age transcribed as 3 same as her sister Sarah Jane’s 
Not found a birth or baptism for Ellen Robinson with mn Wright

Could it be a second marriage for her father George or was she the illegitimate daughter of Mary WRIGHT

Sisters Sarah & Mary ROBINSON’s baptism same day
27 April 1861Sarah Jane Robinson age 3 years
Born 20th Nov 1857Mary Esther Jane Robinson age 2 months
Born 1 Mar 1861Baptism Place Birmingham
Residence Place Edgbaston
Church Islington Methodist Church
Parish as it Appears The Wesleyan-Methodist Chapel
Father
George Robinson Mother
Mary abode
Communication RowROBINSON, SARAH JANE
mmn WRIGHTGRO Reference: 1857 D Quarter in BIRMINGHAM Volume 06D Page 63
ROBINSON, MARY ESTHER JANE
mmn WRIGHTGRO Reference: 1861 J Quarter in BIRMINGHAM Volume 06D Page 44
Added - Mary Esther Jane Robinson Age 2, abode St Martins Street
Burial 15 Feb 1863 St Bartholomew Birmingham
1871c Piece 3100 Folio 38 Page number 27
George Robinson 60 Middlesex London Head occ ??
Mary Robinson 38
Worcestershire Dudley Wife
Sarah J Robinson 15 Daughter
Theresa Robinson 5 Daughter
1871c
https://www.familysearch.org/ark:/61903/1:1:V5YH-RGN?lang=en??za Amelia Robinson Born
24 Jun 1864Baptism 31 Jul 1864 Birmingham
Residence Place Edgbaston, England
Church Islington Methodist Church
Parish as it Appears The Wesleyan-Methodist Chapel
Father
George Robinson Mother
Mary Original reads
Thirza Amelia ROBINSON, THIRZA AMELIA
mmn WRIGHTGRO Reference: 1864 S Quarter in BIRMINGHAM Volume 06D Page 11
1881c Piece 2964Folio 70 Page number 31
George Robinson 70 London, Head occ
Gen Labourer Mary Robinson 47
Dudley Wife
Sarah J. Robinson 20 Daughter
Thearsa Robinson 15 Daughter
Charles Robinson 10 Son
Mary J. Robinson 5 Daughter
1881 c
https://www.familysearch.org/ark:/61903/1:1:Q27N-S4ZD?lang=enIs this Mary J birth entry - no mmn
ROBINSON, MARY ESTHER JANE -
GRO Reference: 1876 S Quarter in BIRMINGHAM Volume 06D Page 51
possible death entry for
George ROBINSON age
79 Dec
1889 Aston Warwickshire
There is an 1854 marriage for a George Robinson to Mary Ann Wright ,
both
res. Tonk St., both
single, both made their mark - image on Anc*y
27 Nov
1854 Birmingham, St Martin, Warwickshire, England
George Robinson occ
roadman Father John Robinson
Spouse
Mary Ann Wrightlittleem1906 - please come back and let us know your thoughts