with the registered product, I am able to drag patterns out onto the desktop. I still cannot drag them into GarageBand MIDI track, however, I don't think this is the fault of Arturia and the Spark. I cannot drag a MIDI file into GarageBand even from the desktop, so I assume GB doesn't support drag and drop MIDI.
My solution for use in GarageBand is to export all my MIDI to a folder on the desktop, import all MIDI files to iTunes to a Playlist with the same name as my Project in Spark, and then use the Media Browser to grab all of these MIDI files for use in the DAW.
It's kind of a pain, but at least it's possible!
Thanks for your help,