Had a clutch problem on a friend's Brooklands. It started off like yours but got progressively worse 'till it didn't operate at all. We bled the system & then changed the master cylinder, neither of which cured it. In the end, we took it to Phil Bleazey where we fitted a replacement (Volvo) slave cylinder while having the Centa upgrade done.
Check out this
THREAD for more detailed clutch information.
I have a spare master cylinder if you want to try it? Might just be your problem and it's certainly easier to replace than the slave cylinder.
