I think that divorce in this instance was highly unlikely. I've been advised that until the advent of the Married Women's Property Act, 1927 divorced men were allowed to describe themselves as widowers, as Charles did at his second marriage, though I'm very doubtful that he was actually divorced.
The real nub of the puzzle is that the birth cert for Doris, registered as Perkins Linford did not contain a father's name, which suggests to me that the relationship might have been breaking down by 1909 and that Charles Linford was prepared to take Ann Elizabeth back and even describe her daughter Doris as hi stepdaughter on the 1921 census. This despite the fact that his second wife, Elizabeth Jane Parsons, nee Jones, was still living. She died in 1941.