You can certainly get some international channels if you manually move the dish around to other satellites, but the Sky digibox is not designed for general non-sky reception and a Free To Air receiver would be needed.
The Sky minidish is fine for the stronger satellites in the arc, but manually moving the dish every time you want to change satellite will be tedious, perhaps consider a multi-satellite setup, either with a static dish and offset LNBs, or a compact motorised set up.