I found the following on www.imdb.com
-----------------------------------------------

Trivia for
Tunes of Glory (1960)
The name of the Highland regiment portrayed is never mentioned, although the screenwriter served in the Gordon Highlanders. However, the same regimental tartan (designed for this film) and bonnet badges were worn by the Highland regiment in _Carry On Up the Khyber (1968)_ , and so the regiment in Tunes of Glory may well be the "3rd Foot & Mouth."


John Mills wore his regimental kilt once more, when he portrayed a Highland Officer in a wartime P.O.W. sketch on the Morecambe and Wise.


Alec Guinness was offered the role of Lt. Col. Barrow, but asked for the role of Maj. Sinclair instead; he then suggested John Mills for the other role.


This was the fourth and final film together for Alec Guinness and Kay Walsh (though they both later appeared in Scrooge (1970) they shared no scenes).


Film debut of Susannah York.


The Highland Regiment in the film is un-named but based on The Gordon Highlanders. The writer of the original novel, and the screenplay, James Kennaway did his National Service in the Gordons in the late 1940s and based his characters on the book from the officers of the 1st and 2nd Bns when both units were merged in Edinburgh in 1948. In the film they wear the uniforms of the recently amalgamated Cameron Highlanders (amalgamated with the more senior Seaforth Hldrs in 1961 and therefore a rich source of army surplus kilts & Cameron badges for film and TV for many years to come.) Reference is made to to the Camerons in Inverness during the film to make it clear the unit is not the Cameron Highlanders.