Further to this, in the Apple MIDI Setup utility I can see the MPK Mini listed as "MPKMini2" and it says it is online.
I have tried adding it manually (Control Surfaces > Setup > New > Install...) where there is an "Akai Professional, LP", "MPK Mini" listed. However, selecting it and pressing the 'Add' button does nothing.
Clutching at straws here, but is the issue that the MPK identifies itself as "MPKMini2" and Logic expects it to be "MPK Mini"?
Has anyone got the MPK Mini to work as a control surface?