Etymology of Ghillie Brogue?

[OC Richard]

So I just now went through all my old catalogues, and here's what I found

Leckie Graham 1907
No shoes are mentioned.
Illustrated for Evening Dress are four Mary Janes (quicker to type than "instep strap buckle brogues") and one 18th century style shoe. Illustrated for Day Dress are spats.

Lawrie (illustration dated 1926)
"Box calf with buckles and straps or lacing latchets."
Illustrated are an interesting shoe I had previously only seen in The Highlanders of Scotland, sort of halfway between Mary Janes and Ghillies.

Fraser Ross (illustrations are in the style of the 1920s)
No shoes listed.
Illustrated for Evening Dress are slip-on buckle loafers and Mary Janes.
No Day Dress shoes shown.

Andersons 1936
"Patent Brogues, either lacing or buckling."
Illustrated with Evening Dress are Ghillies with buckles.

Paisleys 1936
"Box calf lacing brogues" listed.
Illustrated are ordinary brogues, brogues with flaps, and Mary Janes.

Rowans 1938
Illustrated are Ghillies with buckles, slip-on buckle loafers, and Mary Janes for Evening, ordinary brogues for Day.
All are simply listed as "brogues".

RW Forsyth (illustrations are in the style of the 1950s)
"Buckled brogues" and "lacing brogues" listed.
Ghillies without buckles are shown worn in Evening Dress (the first occurrence of such).

Tartan Gift Shop (Edinburgh) (illustrations in the style of the early 1960s)
No shoes listed.
Illustrated are plain brown brogues for Day Dress and Ghillies without buckles for Evening Dress.

Geoffrey Tailor 1983
"Ghillie brogues: day, heavy; day/evening, medium; evening, light."

(When I bought my first pair of Ghillies in 1976 the shop carried the Keltic brand, and I was offered two weights.)

(This 1983 Geoffrey Tailor is the earliest catalogue I have offering what we now call "semi-dress" sporrans, which they call "day/evening" sporrans.)