I have just ordered an Alpine replacement camera (HCE-C125) and hope to self fit next week.
It is a bumper off job from what I have read.
To remove/refit rear bumper
1. From inside the boot, remove the trim panel from around the latch mechanism, and disconnect the harnesses to the rear fog and reverse lamps, parking sensors and reverse camera.
2. From within each rear wheelarch, release the single fixing securing the lower edge of the bumper to the subframe bracket, and the two fixings at each side securing the diffuser finisher to the diffuser. Also release the single fixing securing the top edge of the bumper to the clamshell flange.
3. From within each side of the boot, remove the two grommets, and release the two fixings securing the bumper top edge to the clamshell. Also remove the single screw just outboard of the tail lamp.
4. Remove the 5 fixings along the rear edge of the boot aperture, clamping the bumper to the clamshell.
5. Carefully withdraw the bumper from the clamshell. 6. Refit the bumper in reverse order to removal, adjusting the panel heights and gaps as necessary.