I just fitted a new clutch to my series three and I purchased an ACS (Australian Clutch Services) kit through Bursons.
For anyone looking at replacing the clutch in their series 3 I thoroughly recommend this brand (ACS).
The old clutch I removed, although having a break in the diaphragm was still very soft, but this new one is divine,.
smooth to release, soft under foot, and gentle on the take-up.
Not a bad price either.

Cheers, Mick.