Agnes Herbert

[Jojopaz]

... you both gave me different information which all came together to lead to the person I'm looking for.   

[Finian]

It seems to be that Agnes used Marion and Maude interchangeably as her middle name.
At the baptism of their daughter Francis Hilda she used Maude, see https://www.familysearch.org/ark:/61903/1:1:685P-KPCP
At their marriage in 1885 in New York City (more than two years after the birth of Frances) she used Maude, see https://www.familysearch.org/ark:/61903/1:1:Q2CJ-XKM6
At the baptism of their 2nd daughter Lilian May Warden Stileman in Jersey she used Marion, as has been posted already.
I believe the 1911 census entry for an Agnes Marion Stileman, already referred to in a post, is her. Although she is listed as sister of the head of household Charles Rushton 57, she is in fact half-sister of his wife Emily Edith (nee Smith), age 41, b. Ealing, see https://familysearch.org/ark:/61903/1:1:XW8R-XQS.
Charles Rushton married Emily Edith Smith Q2 1889 in Camberwell, FreeBMD births, Q2 1889, vol 1d, p 1150
In the 1871 census Agnes M Herbert age 11 is listed as daughter of the head of household Edward Smith (and his wife Matilda Smith) but two of her brothers (Francis J Herbert 16 and Edward Herbert 9) are listed as step-sons and she must have been a step-daughter, see https://www.familysearch.org/ark:/61903/1:1:VFXS-3PY There is a younger daughter Emily E Smith age 1, b. Ealing and this is the half-sister she is visiting in 1911.
A Matilda Herbert married Edward Garland Smith in St. Geo. H. Sq. district, FreeBMD marriages, Q4 1867, vol 1a, p 485.
Agnes's parents were Francis Herbert who married Matilda Dixon in Q1 1854 in Kensington, vol 1a, p 44. Dixon may be a misspelling of Dickson as https://www.myheritage.com/site-family-tree-840926321/davies?familyTreeID=1&rootIndividualID=1500077 gives her mother's maiden name as Dickson.
I believe Agnes died in Croydon Q1 1934, age 75, vol 2a, p 679 but I can't find confirmation that this is her.