I searched "Lady Munro" in BNA, looking at 1926, thinking that I might find a Christmas prize-giving. I haven't found anything specific, but there is clearly a Lady Munro who is very active that year at local events in the Airlie area (cake sales, baby shows). She seems to be the wife of Sir Torquil Munro of Lindertis, Kirriemuir, who had succeeded to his estates in 1925.
Obviously this is quite a distance from Nairn, and it isn't the same Lady Munro that you have researched.