Charles Grey (1849-1923) was born in Norfolk, England. His father was also an organist.
He taught at the London College of Music, and published quite a number of compositions, most of which are of a light nature.
I'm afraid that I don't have any other information about Charles Grey. He was prolific and published a large number of works, almost all of them being of a "light" nature.
"Grande Marche Triomphale" can be found in the "Silver Album" of organ pieces, published by Schott in 1915.
It is as the title states, a "grand march" which frames a little, more melodic central section.
If you're looking at the score, you'll notice that almost every phrase has lines that require the playing of octaves. Sometimes, the octaves are played by the same hand, as in the external sections of this piece. At other times the octaves are played by both hands, as in the central section. Here, the melody is "doubled" between the tenor register in the left hand, using three different solo stops for the three "sections," and doubled in the right hand, which also plays accompanimental chords.
Assuming you like/accept this style/period of music, this is really quite exciting and effective.
You do have really "drive it" or "roll it" to make this work. If you just plunk and play it, it could easily be a dud. :-)
The score is attached below, as well as what MAY be a photo of Charles Grey.