Dollshead clutch - identification

AMC-Norton clutch which has had the main basket lightened a little, with those large curved cutouts.  The pressure plate and spring nuts look like AMC, lightened with lots of drilled holes.

The AMC clutch is a lightly modified version of the Norton clutch which would have been the original on your 'dolls head' box.  Depending on the year of manufacture, it may have the friction material inserted in the chain-ring and 'outer' plates, or friction material bonded to the back plate and 'inner' plates. 

Your Ariel Norton-AMC clutch has the usual Manx mods, lightened basket and vent holes in the pressure plate. Hard to tell from the photo how many plates it has. The Manx clutch has fewer plates than the road going Dominators and later ones had even more plates. Another usual mod was to throw away the roller cage and fill the bearing with as many rollers as possible. I think it was around 50 rollers. As it runs dry it can run with quite soft springs without slipping.

About your other bike, it could have a different clutch. You says it is terrible but not what problem it has. If slipping it could be as simple as too much oil in the primary case, worn friction pads or too weak springs.  If dragging it might be warped plates or maybe too thick oil. If too hard to operate the usual problem is routing of and oiling of the clutch cable. Or a clutch lever with wrong fulcrum to wire nipple distance. Norton clutches are usually quite easy to adjust not to drag or slip compared to some other marques. If you look at Andover Norton, pre featherbed models you can find drawings on some clutches.