Thanks Sue
I guess I hadn't thought of this option (i.e. George William Kelly dying in Whitehaven, but it certainly fits. Yes, Mary Elizabeth (Kelly?) is "mine". The way I have it is that Mary Martha Treloar married George William Kelly in Feb 1868 and Mary Elizabeth Kelly was born in Mar 1868, only one month later. Then I have Mary Martha Kelly, marrying a Charles Costain (from Whitehaven) in 1875 in Whitehaven with Charles and Mary Martha with a daughter Mary Elizabeth in the Whitehaven, 1881 census. Since I have a Mary Martha Costain in my tree I was speculating the connection, which now seems to fit.

Will now pursue getting a copy of the George William Kelly death certificate to confirm.

Thanks for your help.

Wayne