HI Peter
I have finish my self build motorhome on a Fiat Ducato and have fitted 2 rear camera's one for reversing and one rear review.
Both from eBay radio linked and are very good with minimal wirering. Both go to one screen and just change over with a press of a swich on the screen.
Hope this helps
Peter Balfour

Hi Pete.
I know this doesn't help at all,
I bought a camera with a screen that clips over the interior mirror it isn't wifi because at the time lots of people said the wifi systems were rubbish and didn't last long before giving up.
Another reason I bought it was because it has a separate switch to switch it on whilst driving, so I could check my boat whilst on the trailer behind, or just to look behind without being in reverse.

However I never fitted it, been in the shed 2 years, I will hook it out and see what make it is. It was highly recommended at the time and wasn't cheap!