I read your post somewhat late. For the record Edward was my Great Great Grandfather. His DOB, if his census and marriage and death documents are to be believed, is around 1849-1852. As there is no Edward registered for that time, we are forced to consider the Edward born in 1844 to John and Sarah as you have indicated. However, it is odd that he consistently took off 4 or so years from his age throughout his life.
Apart from his military record, I only found a newspaper article (minor offence). Do you know anything else about him, and, indeed, any of his family?