It will. It has been getting slightly worse.
I left the car for about 3 days ,started it, depressed the clutch,tried to engage a gear, just heavy grinding.
Pumped the pedal about 10 times and all ok.
Bled the system, again fine.
This morning,the wife went to work in it. Stopped for diesel, came out and it wouldn't go into gear.
Started it in gear and drove home .
This led me to believe it is a master/ slave issue - but no obvious fluid loss.
The fluid was nearly black in colour.