Flyrod, "Barren Rocks" is fairly easy in the first two parts - and that's what's most commonly heard - it's the second two parts that get really busy. Lots more doublings and dot-cut, in both the Seaforth's and Scots Guards arrangements.

To the OP, I'm not familiar with the competition requirements in BC, but if it must be a single 4-parted tune, may I suggest a fairly recent composition called 'Pipe Major Robert Caudill'? It was written by my piping instructor, Karen Brumley, and published in Bruce Gandy's Contemporary and Traditional Music for the Highland Bagpipe, volume 4. It's very accessible to the beginning piper. It was written in honor of the long-time Pipe Major of the Louisville Pipe Band, who has now moved on to other musical endeavors.

Best of luck on the boards!