OK, really bugging me, now. I've seen this so many times. I know what it is, dammitt.....

 

It has to be some kind of luggage/carrier clamp.

The profile of the bracket is shaped to curve, and then has that bend in the rail. The wingbolt suggests it slides on and clamps down, but is quickly and easily removed, and the whole thing is comparatively hefty.

The paint (weatherproof Hammerite?) suggests an external carrier. Maybe a roof rack clamp for a tyre? It looks big enough...

 

 

 

 

3 hours ago, J.R. said:

The paint colour matches what exactly? The exterior of your car?

 

No paint on the underside means it was sprayed on a flat sheet like that which goes with my observation that its a low volume piece, it has not been powder coated or if it has then it was assembled to a mating piece during the process.

 

Check the pitch of the holes, do they correspond to the headrest rod centres?

 

If they do then mac11irl is correct.

Ftfy

I did suggest head rest first

 

The fact that it has apparently arrived with the car from the factory for me rules out a customised thingamebob left by a previous owner or courtesy car user of a demonstrator.

 

It looks very much like a wheel clamp. But i cant find anything that would match that...

Perhaps this is one for the 'What is it' segment of Al Murray's Great British Pub Quiz🤔

It looks like the rear seat handle that slides the seat forward/back. There metal and the same size ish