Hi Drummo, I am new to this forum. I stummbled across your postings while investigating my husband's family tree and although not confirmed I think I have some information which might help you.
My husband's Great Grandfather, George McKenzie, married a Margaret Drummond in Falkirk in May 1895, at that time she was a domestic servant and her usual residence recorded as Callendar (Perthshire) she was 22 when she married. Their marriage certificate shows her parent's as James Drummond, occupation Colour Sergeant, 92nd Foot Regiment - deceased. Margaret's mother was called Jane Roy. This led me to search for more information on Colour Sergeant James Drummond and that's when I came across this site and your postings. I believe that the James Drummond you are investigating to be the same and that his daughter, Margaret is my husband's Great Grandmother but I'm not sure. Further information found on the web shows that Colour Sergeant James Drummond had a wife called Jane and one of his daughter's was called Margaret.
The 1891 census shows an 18 year old Margaret Drummond as a domestic servant in Huntingtontower House, Tibbermore, Perthshire. This village being remarkably close to Colour Sergeant James Drummond's own birthplace (Auchtergaven/Stanley/Redgorton vicinity - 13/8/1839). The census shows her birthplace as Aberdeen which threw me slightly as I assumed she'd have been born in Perthshire also. I believe however that Colour Sergeant James Drummond and his family did live in Aberdeen at one point. Perhaps I'm clutching at straws but I wondered if she had returned to this area after the death of her father?
George McKenzie and Margaret Drummond had a son called Charles Drummond McKenzie, my husband's grandfather (Falkirk 1911). If I am correct my husband is a great, great grandson of colour sergeant James Drummond. Do you have any information which can assist in confirming this?