I notice Alexander and Mary had a son Charles - 8 in 1901 - if you are researching this family - do you know if he was this one:
Name: Charles MCGURK
Regiment, Corps etc.: Highland Light Infantry
Battalion etc.: 8th (Lanark) Battalion (Territorial).
Birthplace: Omoa, Lanarkshire
Enlisted: Shotts, Lanarkshire
Residence: Newarthill, Lanarkshire
Rank: PRIVATE
Number: 7471
Date died: 30 December 1915
How died: Killed in action
Theatre of war: Gallipoli
He also has no next of kin information on CWGC - but he does appear to have a will in the National Archives of Scotland
SC70/8/200/87 Will of 7471 Private Charles McGurk, 8th Bn. (T.) or 1/8th, Highland Light Infantry, Cause of death: Killed in action, Gallipoli, Turkey, Theatre: Gallipoli., 30 Dec 1915 16 Aug 1915
Don't know if this helps or muddles things up??
Cheers Again
Sue