"The cat is out of the bag!" - :( loose ribbon cable (Image 1 red)

Lift the top hinged lid (not just the scanner lid)

Remove any power to the printer and use a long flat bladed screw driver to release the cartridges - move them into the centre position (Image 2)

Follow the general advice on this video (https://www.youtube.com/watch?v=n3bQ0n41...) to release the printhead park lock but be aware your printhead on the C315 will be on the right hand side not the left

Remove the cartridges by pinching the ends with thumb and finger, then lifting upwards and out

Now remove the printhead cartridge carrier tray by pushing up on the grey tab above the pressure point (label) (Image 3)