It turns out that what I liked so much when we played it in band is a 'tone poem'* that adapts four old Manx folksongs: "The Good Old Way", "The Manx Fiddler", "Sweet Water on the Common", and "The Harvest of the Sea". The tone poem compilation/orchestration is by Haydn Wood, a once-popular composer in the earlier parts of the twentieth century, and dates from as long ago as 1933 (and hence was already more than forty years old when the Magnolia High School Band tackled it).
The question now becomes, how to get it? Itunes has several versions available, but one is the Vaughn Williams piece and the others are somewhat syrupy performances. One online site ("The Sheet-Music-Store") has the sheet music available, but only if you buy the entire band score (all thirty-two parts); there doesn't seem to be a way of getting just, say, the clarinet part or the master (band director's) score. ArkivMusic.com, an invaluable source for out-of-the-way classical music (e.g., Joseph Holbrooke) has a recording of it on one cd, but again their version errs towards the softly symphonic.
A much better idea of what the piece should sound like comes from various entries on you-tube; here's the one that I thought sounds the best:
So, now I've found it again, but the search for a good recording I can put on my i-Pod or play on the stereo will continue for a while.
current audiobook: The Gospel According to Luke.
current book: TROY AND HOMER
*not to be confused with the choral piece of the same name by Vaughn Wms