Perhaps they married as Henry E Collis and Edith Knowles, Sep qtr 1920 Epsom?
Not at all sure these are the right people.
Better for yscollis to come back & tell us what is known of the family after 1911, I think.
Did you get a PM from Yvonne (yscollis) ? The marriage in 1904 Croydon is the correct one , Rose's mother died in 1914 , and they moved in with Emma Collis ( Henrys mother, but she died , Henry went off to war , and Rose' disappeared' till marriage in 1927 She didn't return to her father after the war or stay with him with his second wife Edith . So you were correct in the 'upheaval' theory
I suspect that as she was a child someone either 'took her in' , or the authorities sent her to a home till she was older then she probably went into service