I've got a temporary subscription to Find My Past. It has the newspaper index and pages.   I have found a reference to "Scotland the Brave" AS THE FORMAL TITLE of Hyslop's 'song'. ... "Following stirring and patriotic song".   It then has Hyslop's words claimed to be a fresh work under the STB name - when the were in fact published decades earlier in 1821 by the Scots magazine under the completely different title.   This is in the Dumfries and Galloway Standard of 9th November 1859.

From the early 1860's - 1880's (before the known printed editions) there are then numerous entries for a music theater song of the name 'Scotland The Brave', and a military band tune which is stated to be a march - and associated with a number of regiments.