I am having similar trouble. I used the RPM from enothen, and everything appears to work correctly, except that no displays appear. I checked xrandr and Fedora's settings interface.
Miles, what graphics driver are you using? I think running this will show you, under configuration. I am using nouveau.
I have the encrypted DisplayLink logs with increased verbosity if it'd help anyone.
Laptop: Lenovo ThinkPad W520
DisplayLink adapter: Lenovo ThinkPad USB 3.0 Dock
OS: Fedora 22
Kernel: 4.1.5-200.fc22.x86_64