Thanks for the input so far.
There is no adjustment at the pedal so it appears as if I am looking at three possibilities:
1 Master cylinder worn at top of stroke therefore pushing less fluid than is needed to disengage the clutch...easy to replace, not too expensive, probably due at some stage soon anyway
2 Slave cylinder ditto...awkward job (That top bolt is virtually impossible to get a spanner on... lucky I have long fingers and the surgery to implant double joints in my wrists, elbows and shoulders was succesful. I am looking for a prosthetic hand in a two year old size.), relatively inexpensive, if it was leaking wouldn't the clutch gradually engage itself if the pedal was held down?
3 Clutch plate etc. components worn... BIG JOB!, expensive, it seems to work fine except for the low engagement problem
How does my reasoning & diagnosis sound?
Unless someone suggests otherwise I will tackle it in that order and let you know how it goes.
87 560SEL, 02 ML500, 93 180E