Clutch pedal sticking down with a difference

Ok guys, I have been having several issues with the clutch on my fl2 thought it was the slave cylinder so had a camera inside and there were no leaks checked the master cylinder and there doesn’t seem to be any leaks there either? I have checked and change the seal Union that links the slave cylinder plastic pipe to the copper pipe that runs along the top of the gear box as that did seem wet! However the problem still seems to be there? so I have checked as far as I can see the pipe from the flexie pipe to the master cylinder which I can’t see much of it however there does seem to be a greasy oily substance behind the bulk head? Any ideas what might have gone before I star to dismantle or is it buy it all and replace?