If anyone's interested I removed the head unit in my C1:
So Removal is pretty simple.
Photos of the HU and surrounding areas:
If you find the picture I have circled.
Pull towards you or use a pry tool to release Green first.
Then move down the side with your pry tool to release blue
Then move down the next side to release purple
RED pay close attention to as they need prying UP with a small screw driver or pry tool LAST..
Dont forget to disconnect the Brown circle to pull the part full away.
Headunit like other forums suggest is a AVH - 7148 Toyota branded. It runs on Linux.
There is a unused connector on the rear of the headunit at the bottom, I assume for rear speakers?
I have the highest spec C1 with all options selected bar Automatic gearbox.