Something else I have noticed. When the car is cold (ie. when driven first thing in the morning) the clutch takes up where you would expect it to. As everything gets warmer the take up point gets higher. On the occasions when I have detected some clutch slip, it has always been after driving the car for maybe over an hour in warmer weather conditions. These conditions result in the clutch engaging right at the very top of the pedal travel. This sounds to me like a hydraulic issue, almost as though the fluid expands and can't get back through the master cylinder to the reservoir. Possibly the constricted hose problem? I would expect that if the clutch was worn out, it would not be affected by temperature, and the take up point of the pedal would not change. It definitely only slips when the take up point gets too high.
107.023: 350SLC, 3-speed auto, icon gold, parchment MBtex (sold 2012 after 29 years ownership).
107.026: 500SLC, 4-speed auto, thistle green, green velour.
124.090: 300TE, 4-speed auto, arctic white, cream-beige MBtex.
201.028: 190E 2.3 Sportline, 5-speed manual, arctic white, blue leather.
201.028: 190E 2.3, 4-speed auto, blue-black, grey MBtex.
201.034: 190E 2.3-16, 5-speed manual, blue-black, black leather.