Got it all updated now. A few times after unplugging and replugging it didn't seem to go into 'Firmware Update Mode' for some reason but after several attempts I got it to work.
To know you are in 'Firmware Update mode' and able to proceed with the installation you need to look for the HOLD, SHIFT, OCT- and OCT+ buttons flashing in a circular fashion. I waited 20 seconds or so once the flashing had begun and then clicked update and the installation completed after about 30 seconds.
Hope this helps some other OSX users.