Fitting reversing camera in Ibiza mk4

I’m hoping someone can advise on fitting a reversing camera on a Seat Ibiza mk4. I know this is a mx5 forum but contributers here seem more helpful and friendly than the Seatcupra forum.
I’ve upgraded the head unit on my wife’s Ibiza mk4 and ran video cable the boot. The issues I now have are connecting to the reversing light and its associated earth, and then getting the wiring to the camera on the outside. I want to accomplish this with minimum holes and disturbance to the appearance of the car.
I’m hoping someone will have done something similar and can advise.