2013-2017 UPDATE
his is proving a real challenge!
So my research still continues with only teeny clues and clarifications since 2013.
I now have a copy of James & Dora's original marriage certificate as the Sydney Anglican Church has digitised their records, very fortunate for me as these records were archived and not easy to obtain. It clearly states James parents as John Thomas Blunt and Mary Cunningham. I was uncertain from the BDM record if his mother was May or Mary so it is good to have a teeny new clarification. I also now have an original signature for James Matthew Blunt.
I have also obtained the adoption rights for my grandfather and now have his original birth certificate. Unfortunately although it states his parents as being James and Dora the only different information is a James age is stated as 34. It was stated as 36 the year earlier in his MC, the same as Dora. The BC states 36 for Dora. does not have any new information. It also has a name change of my grandfather as he was adopted. But this change is noted on the BC.
At least it shows some consistency between the three records I have, but suggests I need to keep a time frame for birth from 1879 to 1884 for James
I know for certain that the James Blunt from Wabash Indiana, who seemed to be the only possibility, died in 1949 and was buried in Hicks Cemetery Perrysville, Vermillion County, Indiana, United States of America and is buried there alongside his parents and brother John.
I have researched many Blunts living in Australia without success.
My database of J Blunts who traveled to all ports in Australia from 1880 to 1916 is still hypothetical without any real clues. I can't be sure if he was here for 20 years before his death as the informant stated on his DC. I still haven't found any electoral roll, Sands Directory or naturalisation records for him.
So we continue our research hoping that new information may appear over time, which it has but I really do not know where else to look.
Any other suggestions would of course be greatly appreciated.