Sorry for the long wait with a reply.
Since I posted that message, I came in contact with another person who was following the Nepean-Hutchison surname. I have now info on some of the Hutchison's back to 1799. I found that Hutchison married into Hutchison. The wife is from Scotland but I don't know where the husband is from.
It is making life interesting though.
I had followed the Nepean's back as far as I can. I think Anna Nepean's gg grandparents are Henry Nepean and Frances Dodge.
What line of Nepean's are you descended from? do you think you might be able to help me more with the Nepean's?
look forward to hearing from you.