4 months on and the clutch is still slipping.
I thoroughly inspected the clutch cover & plate, made sure the release bearing was retracting easliy and fully and put the clutch back in the car. The operation is smooth, biting point was in the right place and if driven gently doesn't show much of an issue. Start to push on and it slips fairly easily at low revs when the torque is highest.
Today I have removed the box again - it nearly jumps out by itself now, and was going to try the clutch that was in the car when I bought it (had to remove the engine, so replaced the clutch while the unit was out of the car just as a matter of routine) to see if that solved thr problem which would probably mean weak springs on the clutch cover.
Now I have looked at it the previous clutch cover does show some signs of slipping on the inner edge so am a little reluctant to put that back in.
Any further ideas, otherwise I suspect I'll be putting a new clutch in tomorrow, which I am reluctant to do as I cannot say I think I have actually identified the fault.
I seem to remember that LUK clutches are decent quality. Sachs is OEM, but doesn't appear to be available from EuroCarParts - thoughts ?