Thanks Strophoid. I checked what you suggested. Yes the notes line up if I play along, but the audio as I play the midi keyboard notes is delayed. I have tried lowering the buffer size on the Focusrite all the way down as low as it will go, but the audio is still delayed and if I lower the buffer below 512 it starts distorting anyway.
I am thinking I need a keyboard that will plug into the midi input of the Focusrite, rather than the usb port of the computer. If I can’t get this MPK working properly in the next day or so it is going on to ebay. I don’t think it is compatible with my firewire interface.