That's quite a decent ceremonial piece. I think in a real-life performance it has to sound pretty good, especially in a large hall. I can also imagine it being played by a full brass section, timpani, gong, or strings instead of the piano. For a more powerful effect in GPO, you could try to overlay the trumpets with the Trumpet Overlay instrument.
There is one thing less ceremonial about it: the piano chords first heard at 0:25. That makes it temporarily rather comic. Was that the intention?