When the CG Tuba Quartet played at an ITEC (then T.U.B.A.) event in California in 1978, I was lucky to be able to hear the Hollywood Tabernacle Band of the Salvation Army perform with Wilfred Mountain as soloist. I bought the LP of the group at that time, which also featured Wilfred. This is from that LP. I assume it was recorded somewhere between 1976-1978. The piece was written by Philip Catelinet (also a Salvation Army guy). His photo is below (click to see a larger size), from the Euphoniumists Dinner in London, 1980. My wife and I had lunch with him the next day, and had such a nice time. Catelinet was a great gentleman and a delight to talk with!
This is a fairly extensive piece, and is one of the early serious works written specifically for euphonium.
https://youtu.be/_Pq2XPzCwu4