[blykins]

Slave cylinder?

You may want to check the geometry of your clutch fork/slave cylinder setup. It may not be the slave cylinder's fault. Wilwood makes a great slave and I've used them for years.

Also make sure that the clutch was adjusted correctly. If it's a Long style pressure plate, as the clutch wears, the fingers actually get closer to the throw out bearing.

Having said that, no manufacturer is perfect, so you could have got a bad one. But it's worth checking out other things first just to make sure.