Hello, Janine,
It is possible that Henrietta Elsie Collins married Herbert Lee.
The names of mothers are entered in the birth indexes after Sept ¼ 1911 so if you find a marriage in the freeBMDs giving you the choice of two spouses, you can try trawling thro' the birth entries after Sept ¼ 1911 making a note of all the those with the two spouse names in the relevent district.
I could find nothing with Dean/ Collins as parents but there were several for Lee/Collins. I only went as far as 1916, there may be more.
Susan A. Lee
June ¼ 1912 Edmonton 3a 1357
Charles E.R. Lee
Dec ¼ 1915 Edmonton 3a 1051
Elsie A. Lee
Sept. ¼ 1912 Edmonton 3a 1082
The second two may be brother & sister, the page nos are not too far apart, Elsie is perhaps a clue here as well.
The Susan A.Lee may be another family as the qtr. & that of Elsie are too close in the same year.
Hope this has helped.