Just checked in to the Newbold message board and found your posts about your visit to Burlington, NJ, your connection to and interest in the Newbolds.
My grandmother (Margaret Caroline Newbold) was your grandmother Dorothy's sister. My mother Joan talked fondly of her visits with her American cousins, including your father Arthur.
I am fortunate to have inherited quite a lot of published Newbold information, some wonderful photos (including a few of your grandparents I think) from my grandmother and to correspond through this forum with a couple of my American cousins.
All this information started my life-long interest in family connections. Let me know if I can add anything to your search.