Im with Alec I have disnmantled engines from all sorts of cars and never seen wear on a thrust bearing with so little running on a properly assembled engine. I guess that excessive use of the clutch may add to the wear but not cause it. The load is surely off the crank when the clutch pedal is depressed so starting with the clutch depressed would unload the crankshaft to its neutral end float position meaning that although the oil pressure is at its lowest the load is also at its lowest. A point to argue but hardly a cause of what amounts to almost instantaneous catstrophic bearing failure (instantaneous considering that many of these engines will do 3 or 4 times the mileage without significant bearing wear) If you consider what is happening to the conrods and little ends when the crank shaft floats backwards and forwards and this isnt the first time youve seen this wear are the little ends also worn in the rods or are the rods bending! Careful measuring inspection of crank journals, radii, and conrods and gudgeaon pins and althought this sounds like a stupid suggestion, the Stag manual does warn the trained BL mechanics, to ensure the conrods are ALL assembled on the crankshaft the right way round.