Does the media selection become available if you connect a USB drive with media on it?
This is a significant difference to the I-MIEV, as this was supplied with a Pioneer generic head unit, that is not coded in any way, nor has Bluetooth, nor has any connectivity menu - i.e. a very typical older gen CD radio head unit.
Does the car come with a head unit manual, and if not do you have the keys to remove it to find the manufacturer and model number, then try looking on the manufacturer specific website.
Just wondering if these were fitted in the factory in Japan, or at the dealerships in the UK. The 4 holes remind me of the old Blaupunkt removal keys.
I'd put my money on it either being Blaupunkt or Clarion.
If it is Clarion, it would be somewhere around here:
http://www.clarion.com/gb/en/user-support/software/CZ201E/index.html