Hi Bob,
It seems that the design changed over the years and became more crudely made. According to my late Craven catalogue the set up in Original Vincent p24 tallies. The Rapide PAE 48 appears to be modified with lugs brazed or welded on to the mudguard/lifting stay for the rear carrier stays. This is a much neater and more secure arrangement than the standard Craven clamps, which can slip down. The seat nose spindle bolt needs to be longer as the carrier arms are fitted outboard of the spindle nuts and secured by a second nut and washer. Without this spacing the arms may foul the springboxes.
The long arm from the seat nose goes inside the seat stays using the cranked mounting plate which is attached to the seat stay top pivot using a longer 1 5/8" bolt (963) and then on to the front pivot on the carrier. On PAE 48 it is mounted on the outer side of the pivot plate. Mine has to be mounted on the inner side. This seems to depend on the vagaries of the the dual seat mountings and seat stays. The rear carrier stay has a bend with a long and a short side. As with PAE 48 the long side uppermost seems to suit the twin whereas the short side uppermost seems better on the Comet. On some bikes the hinge tommy bar is likely to be wiped off on the first big bump and is best swapped for the long 'D' nut (which is shorter). This rear stay is mounted to the outside of the carrier pivot plate. The pivots on late versions comprised of a fully threaded bolt, 2 plain nuts, washers to taste, bush and locknut. Early bushes were Oilite, later bushes were bronze some flanged, some not. All of them wear quite rapidly and need frequent lubrication. Unfortunately as they are such a hassle to set up and need dismantling to lubricate this is often neglected. Setting up the pivots is this - Bolt, washer, pivot plate (or clamp), washer, nut, nut as locknut, washer(s), bush, Stay over bush, washer(s), Nylocknut and there are six of the B-----s.