12 years!!
I do hope you are still out there Edward, and that you are further along now!
I am also researching the JACKSON families in Devon, and in Newfoundland, But I haven't got as far back as James in 1744! I do have some direct ancestors called James JACKSON, so it just could be the same family.
I have a Dorothea Burgoyne JACKSON (1778 - 1782)
born 14 Jan 1778 at Trepassey, Newfoundland, Canada
bapt 25 Feb 1779 at Topsham, Devon, England
died 24 Jun 1782 at Topsham, Devon, England
Her parents are James JACKSON (born abt 1750, died after 1806), and Sarah MILLER (born abt 1750, died 1806, Topsham) They were married in Topsham, Devon in 1775.
James is listed as 'Merchant' on his Marriage Certificate, and the birth of Dorothea in Trepassey confirms his connection with the trade between Topsham and Newfoundland
However, I've been unable to find any information about him or his time in Newfoundland, and wonder if anyone has any suggestions. I do have his later children, all born in Topsham, Devon, and the tree is quite leafy from them down!
Best wishes
Gene