I am going based on a little searching and memory (forgive me..it isn't what it used to be LOL)
Usually a horse that was called "Cadet's" something or other had Cadet Commander in the bloodline. Commander was very well bred:
Sire: KING OF THE HIGHLANDS -[uS]M2344-
who was a great one..his breeding is:
Grand Sire: KING OF THE PLAIN (IMP) -[uS]M2242-
Grand Dam AXHOLME VENUS (IMP) -[uS]F3641-
(Note (IMP) indicated British bloodlines..King of the Plain was and still is a tremedously potent influence on the Hackney breed..put the square trot on them!
Cadet Commander's Dam was Imported from Britian:
Dam: PENWORTHAM'S DREAM (IMP) -[uS]F4174
Grand Sire: SUCCESSFUL -[GB]M8314-
Grand Dam: PENWORTHAM DOT -[GB]F26420-
As I mentioned, I am just going on the assumption that "Cadet's" follows back to Cadet's Commander...
Kim