Well after getting though 3 clutch slaves in as many months i reckon the problem has been found. ok so i have done about 6k in 5 months on it but this was ridiculous. My 95 916 was destroying slaves at an alarming rate and often sticking in the engaged position by pulling the cylinder on a slight angle.
Problem was the clutch center, what was happening was the bearing was knackered on the clutch cover plate so when you pulled the clutch in the pushrod spun up also thus forcing the plunger in the slave to twist more than it should.
So next time your slave goes west it may be an idea to check the clutch center for a shot bearing and same all that premature wear.
May be of help to someone i hope, and i now feel alot more trustworthy of the ducati and missing the blade less and less with each trouble free mile.