Just seen your message as I have not checked the board for some time.
I have ELGEY connections in Hull but have not come across Mary, Margaret or Cecil as the periods they lived have not been recorded.
My link is through John Thomas Elgey of Burstwick, a school teacher, married Betsy ANDREW in 1877
John Thomas appears to be the son of William of Burstwick and Elizabeth ? and was born 1853.
A brother ? born 1851 at Burton Pidsey was Frederick Elgey Clifford ELGEY ?? who had 4 sons and appears in the 1881 and 1901 census in Hull as a Miller [ Corn ] so there may be some of this family line to trace.
John Thomas was a Dock Lab in 1901, the census has him as ELSEY They had six sons, one killed in WW1 and one in WW2 J.C.Christopher Glass who also posts found some of these from a family member Vince who does not respond to messages.
I have in my data another Holderness family that have a Durham connection. William James Elgey born 1842 Durham, so of Robert b 1844 at Preston by Hedon. William James had 4 sons born in Durham, I think this information may be from Chris Glass but it is somewhile since I entered these.