Actually I don't know all that much about the Shawcrosses. That is my cousin's forte. My grandmothers name was Bertha Shawcross (McPeak) and I had a great uncle named William. They lived in Rhode Island. Shawcross is a family name in my family. My father was William Shawcross McPeak (7-6-14 to 8-11-01), my brother is William Shawcross McPeak, Jr. and my great nephew is William Shawcross McPeak III.
I heard bits and pieces about the Shawcrosses when I was growing up, but my cousin in Rhode Island knows more. She has spent a lot of time researching the line.
Sorry I could not help you out. I was trying to find out if Lord Hartley Shawcross was a relative as I had heard in my childhood.