Shifty would agree with your comments on the clutch and driving technique however I only do about 5000 miles pa in the 90 and drive quite normally. Advanced driver so do not sit at lights riding clutch, use hand brake etc.
Last clutch lasted 5000 miles,before starting to slip. The remap is a JE Engineering with a supposed 175 bhp. According to a couple of well known tuning shops the clutch should take the power easily.
Have just changed the dual mass flywheel, clutch, plate and solid thrust bearing so will see how long it lasts this time. At time of change of clutch there were no oil leakes which could have been part of the problem.