Florence Ann Compton was orphaned who were her parents?

Background

Family history is all about establishing relationships and we use a selection of records to "prove" the members of a family.
In this post I want to discuss some documents I have used to answer the following question.
Who were the parents of my grandmother Florence Ann Compton.

Documents

In order to meet the challenge of 3-2-1 CITE I will only discuss 3 documents even though there are others in my collection that may further support my proof argument.

What the documents say about the family relationship

1. The census document has the head of the household at 6 King Street, Warminster as Edmond or Edward Jno Compton and his wife is Thurza Ann. The children are listed as Walter Jno 9, Sidney Herbert 7, Stanley James 5, Ernest Roy 3 and Florence Ann 1 mo.
2. The birth certificate shows the birth on 17th February 1901 of Florence Ann Compton daughter of Edmund John and Thirza Ann Compton formerly Robbins at 6 King Street, Warminster.
   
3. The baptism at Christ Church Warminster on May 16th of Florence Annie daughter of Edmund John and Thirza Ann Compton, 7 King Street.
   

The Evidence 

The census record indicates that Florence Ann Compton was born in February or March 1901 as the 1901 census was taken on 31st March 1901. The names of her parents differ only slightly in terms of spelling to those given on the birth certificate and in the parish magazine. The census and birth registration would have been recorded on consecutive days by different officials. The baptism was recorded within 2 months of the other records and all three are contemporary with the birth. In the case of the census and the birth the informant may have been the same person, the father and head of the household. The informant for the baptism may have been one of the church officials either clergy or lay member or taken from the baptismal register.

The information on the birth certificate and census regarding the residence is in agreement and the parish magazine only differs by number, which is possibly due to confusion regarding numbering or incorrectly recorded in a baptismal register. (I have been to the street and know that I was unable to find number 6.)

Conclusion

Florence Ann Compton was the daughter of Edmund John Compton and Thirza Ann Compton (nee Robbins).
The actual baptism register would be a more reliable source than the parish magazine and obtaining a copy would further support this proof.

Citations

1. 1901 census of England, Wiltshire, Warminster, Christchurch parish, folio 37 recto, p.9, household 53, Edmond Compton; digital image, Find My Past (http://new.findmypast.co.uk/ : accessed 5th April 2014) ; citing PRO RG13 /1943
2. Register of Births Warminster Registration District, Certified Copy of Entry 184 for Florence Ann Compton, 1901, issued 21st October 1907, digital image: [created 2nd October 2003]
3. Parish magazines for Warminster, Wiltshire, June 1901, page 2, Baptism May 16th Florence Annie Compton, digital image, (http://freepages.genealogy.rootsweb.ancestry.com/~pbtyc/Warminster_Par_Mag/1901_06/02.html : accessed 10th April 2014);