I installed one on a forum members XK a few years ago. They work for a while and then the grit/dirt binds up the cables and it fails.
Good idea but the mechanism is exposed to the elements.

bob

 

Q could make you a bullet-proof one, but you might have to sign up for the Double-Naught Service.

 

Is there a way to weather coat or protect the mechanism, or is it really a lost cause to invest in something like this?

 

The customer was smart to buy 2 and after half a year I installed the second one due to the first one getting full of road debris and cables dislocated.

You will need to engineer some mount brackets to fasten it to the underside of the car. I used some 'new old stock' electric antenna generic mount brackets of flat steel segments with a series of holes. They were bent and bolted to hold the assy in place.

Probably better suited to a show car that is trailered more than driven. I liked it but it should be cleaned/lubed OFTEN!!!!!!!!!!!!!!!!!!!!

bob

 

I have the below on my X150. Basically a manual version of your link. It does work but gets stiff if you pull too close to curb and bang it.

Show N Go Plate Holder: