Down the "Valley of Death" with thundering knell,
Poured a hurricane hail of shot and bursting shell;
With demoniac slaughter and hellish roar,
Through charging ranks of horse and heroes tore.
But "Death or Glory" led the way.
Of Cardigan's dash and dauntless fray,
How Hussar and Lancer bravely fought and fell
The scroll of fame their deeds will ever tell
Of the chivalrous and fearless Six Hundred.
[Source: William Butler, A Descriptive Account of the Famous Charge of the Light Brigade (about 1890). This brief poem concludes his memoir.]
"Death or Glory" is the 17th Lancers' motto.
I have not come across any other references to "G.S.G." — possibly another Charger, or a friend?