This is a long shot, but there is a death of Cathol Magnus Sutherland, aged 93, mother's maiden surname Moodie, in Inverness in 2008, and a birth of Cathol Magnus Sutherland in Kildonan on 1936.
That led me to
https://larcheinvernessblog.blogspot.com/search/label/Cathol%20Sutherland and it occurred to me to wonder if someone at Braerannoch might have some knowledge or record of Cathol Sutherland having a brother who was in the squad who drew King George VI's gin

carriage?
The comments mention a brother Dai. There is a death of David Robert Sutherland, 68, mmn Moodie, in Thurso in 2005, and a birth of David Robert Sutherland in Kildonan in 1936. Might this be Dai, and if so did he have family who might remember Uncle John George and the gin

carriage?
Or perhaps John George himself had family who would remember this story? I wonder who signed his death certificate?