Thanks, Frances, I hadn't thought of looking at Manx Notebook. I wonder if Robert knows that his gggg grandmother, Ann Corrin nee Tyldesley b 1737, had a brother Thomas b 1733 whose daughter Margaret married Benjamin Greetham.

Robert, if I were looking for a reason why Christiana Frances Brown nee Corrin named one of her sons Greetham Brown, then here's a possibility. When choosing godparents for their daughter Christiana, Henry William and Mary Ann Corrin might have chosen one of Henry William's Greetham cousins who were the children of Benjamin Greetham and Mgt Tyldesley (they were second cousins once removed, I think ). At least one of them was alive (a spinster) when Christiana was born. Here's her will:

GREETHAM, Mary Ann 1870 Dgs A 32 0106272

There are 3 more Greetham wills on Brian's list, too.