One wire will need to be fitted to the reverse switch wiring for it to auto screen on in reverse as my alpine had a purple wire for this.
If I were still in brum I would have done it. Stereo needs pulling out and trims need either pulling away or the wire being fed into the trim either way not a simple job and the boot trim also needs removing for wiring and drilling so you don't drill into wiring
There's a guy in Bordesley green who caters for this behind green Lane opposite the morrisons next to the mosque. Just say bello sent you if you do go.
M