"Greyfriars Bobby" was made by Disney in 1961 and tells the tale of a loyal dog sticking by it's master even after death. Although argued by critics as a much made up story (not by Disney), it is still a fun movie to watch with kids.
I picked Alex Mackenzie, who played 'Old Jock', because he didn't even get into acting till he was 61, after finishing a career as a teacher.
Surely someone who started so late would not have time to make a Sherlockian movie connection?
Alex Mackenzie (1885-1965) -
took part in the 1957 movie "Rockets Galore" (by another famous Scot) -
which also featured Donald Sinden (1923- )
who participated in 1973's "The Day of the Jackal"
in which one of our favorite Watson's, Edward Hardwicke (1932-2011) had an uncredited part
So, there you have it, there you are.