Margaret Ann was born 26th September 1871 in Mordington, Berwick. Parents William Cairns and Janet Alison. So her maiden name was just that; Alison.

Can't find their marriage at the minute.
edit: Full birth details
Margaret Ann Cairns
Sept. Twenty-sixth 1871
8:15AM
Edmington (?) Mains,
Parish of Mordington
William Cairns, farm servant
Janet Cairns, MS Alison
24th April 1868 (?)
Berwick Upon Tweed
Registered by William Cairns, father
PM me.
