I drive a Subaru Forester these days, but it's the basic model and doesn't have any reversing sensors. Also, the backward visibility is really poor, which makes reversing into spaces and hitching up trailers really difficult.
Anyway, the eventual solution was much easier than I'd imagined: a wireless reversing camera.
The one I chose was a
Boscam K2, which I bought for £65 from Amazon on special offer. The kit consists of a camera which you mount next to the rear number plate, and a monitor disguised as a rear view mirror.
Installation was a straightforward DIY job - mount the camera and then run cables up to the top of the boot lid and then down to the reversing light, where it connects electrically. The camera then has a wee wireless transmitter which I stuck onto the inside of the boot lining.
The monitor screen just wires into any available 12V connector. It came with a cigarette lighter type plug, so I wired in a new socket behind the dash to accommodate it, and ran the cable up the A-post behind the curtain airbag and under the headlining, so everything is neat and hidden.
Anyway, the mirror looks exactly like a normal mirror until you put the car into reverse, which switches on the camera and activates the screen. I've got it set up so I can see the towball at the bottom of the picture, so hitching the trailer has gone from being an annoying guesswork type job, to a really easy right-first-time one. It's also really useful for reverse parking, funnily enough!
Also, I read online that some people are wiring these cameras into the reversing light of the trailer (or horsebox) itself, so they can see what's behind the trailer when they're reversing. Because the camera is wireless, there's no extra cable to run between the trailer and the car - clever eh?
Anyway, this solved a long standing problem of mine, and I count I count it as £65 well spent. I just thought I'd leave this here, in the hope that it's useful to others.