Lydia Trimble

Hoping to find descendants of Lydia (nee Davis) and Robert Delmege Trimble born about 1820 near Donaghmore and Pomeroy in Co. Tyrone.
They went to Australia in 1841, Robert came home to Pomeroy about 1890, Lydia had a brother Thomas, her father was John, her mother's maiden name was Alexander. I want to find where Lydia's final resting place is?
Robert ( A Descendant)