Mary Ferrett is my fourth great-grandmother she married Philip Upton Ebbott in 1804, in Trenglos, Cornwall thus becoming Mary Ebbott.
As explained in a previous post entitled Two Mary Ebbotts help need to disentangle them I have been trying to distinguish which of the two Mary Ebbotts that appeared in the 1841 was my ancestor.

To recap- In the 1841 Census in Cornwall, there are two Mary Ebbott?s born about 1786 in the county of Cornwall. When searching on the web, I noticed that these two Mary?s are often interchangeable and both often assigned to my ancestor Mary Ebbott (nee Ferrett).
This is further complicated by both of these Mary?s staying with families who are directly related to my ancestors.
In household 1 Philip Ebbott is the eldest male in the household. Mary in this household would be Philip?s wife, and therefore my ancestor. This is corroborated by the 1851 census, where both are listed as husband and wife.

In household 2 John Bone is the eldest male of the household. John is the father-in-law of Sarah Ebbott, Mary Ebbott (nee Ferrett)?s daughter. It is possible that Mary could have been visiting Sarah?s in-laws on the night of the census. John Bone?s wife Grace died two days before the census and this could have been the reason for the visit. I can find no further record of this second Mary Ebbott in the 1851 census or death between 1841 and 1851.

Working Theory
Both Mary Ebbott?s in the 1841 census are the same person who was registered in two places. She may have been staying the night of the census with relatives (John Bone), and was included on the household census. And at the same time Mary?s husband, Philip Ebbott, not following instructions to the letter, may have included her in the household as this is where she lived.
If the head of household was literate then they would fill out the census for the family. This could mean that husband, Philip Ebbott filled the census out as soon as he got it and/or it sat around waiting to be picked up, in the meantime his wife may have gone visiting to John Bone's either for the day or overnight and as a consequence was recorded as being at the Bone's residence as well. The residences being only 3 miles apart this would be have been quite plausible.

I would be interested in hearing other researchers thoughts on my conclusion either in agreement or disagreement, I would be particularly interested in anyone who can claim or recognise the Mary Ebbott of household 2 thus disproving my theory of a double up.

The background to my conclusion
The first step was to trace and confirm the identity of Mary in household 1, beyond the 1841 census. In the 1851 she is confirmed as the wife of Philip. Mary?s husband Philip passes away a two months after the 1851 census, and soon after in 1854 Mary with her youngest son William migrate from Tresmere to Palumyra, Wisconsin, USA via Quebec.
The second step then was to establish or eliminate the Mary in household 2. I looked for a death of a Mary Ebbott between 1841 and 1852 to see if she had died between the censuses. I found only one Mary Ebbott dying during this period. The death registration was for a Mary Jane EBBOTT. This Mary Jane Ebbott was the granddaughter of Mary Ebbott (nee Ferrett) and only 3 years of age. The result being the Mary Ebbott in household 2 remains a mystery.