I cant find the thread or remember the username, sorry.

Anyway, I have the same problem - new clutch kit with new slave and master cylinders.....pedal is nice and light, but gradually the bite point drops over the course of a few days until it needs bled again.
Its a borg n beck slave cylinder and someone on here had the same problem which they apparently solved by changing the quick-release coupling for something else.
The coupling on mine always has a damp smear of fluid on it so I assume it leaks a small amount and lets in air.

What did you use to replace the joint with? The plastic pipe from the master cylinder is 8mm O/D and the pipe from the slave is metal and 7mm O/D but it has a threaded fitting braised on.

Cheers.

EDIT - just had it to bits and the threaded bit for the female side isnt braised on, the pipe is flared and it looks like a standard brake pipe fitting.

The problem with bleeding the TD4 clutch is that the clutch pedal does not push the piston fully down the master cylinder and so any air remains present, or returns later.

I popped the master cyl out. Removed the circlip, took the push rod out but left the 'top hat' that pushes the seal in place. Temp refit the circlip, now the piston can be pushed right down with a suitable rod or screwdriver. It will go down about 25mm (1") more than when the pushrod and plastic skirt are fitted and you can expel the air.

Mine worked fine after this. A new slave should be pre-bled but the join can introduce air when coupling up.

Hope this helps.