spider clutch woes

[AMcvicker@domain.elided]

I have narrowed the shifting problems in my '87 Spider down to a clutch that 
will not disengage. Whereas before it merely ground when trying to get into 
1st or R, now attempts to start while a gear is selected and the clutch 
depressed causes the car to lurch along compliments of the starter. 

I have already bled the clutch line, so I know it is not that simple. The 
manual offers three possible points of failure:master cylinder, slave 
cylinder, or clutch plate. Any ideas on how to diagnose which of the three is 
at fault?

Cheers-
Andrew

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