Now received my new carrier, badged by Towsure, but identical to the Diamant as per the advert.
As these are also being sold under the Bosal name, it seems like the big tow bar companies are happy to have their name associated with the product.
The finish is of high quality - powder coated steel and anodized aluminium. It all seems to work well and isn't in any way cheap and nasty.
The first road test with one bike loaded reveals that it's very sturdy, with virtually no wobble/flex.
A doddle to quickly fit and remove and the supplied bag means that there is good protection for it and other things in the boot.
For £150, this seems like a bargain.