With thanks to the WSC Parts store, here are the main GRP parts...
The frame part screws down to the top of the rear tub, over the normal boot box.it fits around the standard (un-braced) roll bar. It has grooves moulded into it for the hood frame (if you have one), to fold down into. This is the lates ZK type shown, so it also has that stepped section at the front, where you would attach inertia reel seat belts, if you had them. (Note, early lids and frames don’t have this recess for seatbelts, so don’t worry if you see both types.)
The lid section is then attached via a pair of hinges, to the back of the frame. (It opens up backwards, if you see what I mean, so as to clear the hood frame.)
And here it is, in place in a car. It’s an extremely fiddly moulding to make - especially the frame, so I’m guessing the laminators are charging Westfield big bucks now, to try and discourage people from buying.
But, the lid system work so well, it’s a real shame. Mine was so much better than just a vinyl tonneau cover, on my old ZK type tub.