After some more research I have found out Charlotte Rigby and Charlotte Haydon are related. I created the families in a new project in Family Historian and using census records I built the John Rigby and Sarah Morter families. Sarah Rigby, born in 1838, was the third of 12 children born to John and Sarah between 1835 and 1862. I have not shown all of the 12 children in the above image to keep the tree simple. A larger version of the tree can be seen by clicking on the image, it will open in a new window.
In May of 1860 Sarah married James Haydon and I have traced three of their children the youngest of which was Charlotte born in 1876. In 1894 Charlotte married James Price (1861-1895) and they had two children. In 1910 Charlotte then married Charles Lefever. I cannot find a church record for this marriage but have found it on FreeBMD in Q2 1910 Bethnal Green Volume 1c Page 304. However, Charlotte and Charles had their first child in 1902 and had two more before their marriage in 1910.
As a result Charlotte Haydon is the niece of Charlotte Rigby. This marriage was of a type not permitted in 1910 and as a result it would not have been a valid marriage. The marriage to a deceased spouse’s niece was not legalised until 1931 in England. (Marriage Law for Genealogists by Rebecca Probert page 66). At least it wasn’t a bigamous marriage as I have now traced the death of Charlotte Rigby to 1899.