Ford Focus when starting from warm sometimes a clanking noise and the clutch pedal hard

on starting when warm sometimes there is quite a rattle clanking noise it doesn't start and the clutch pedal get hard to push down. switch it off and it may take a couple of trys but it starts and after a few seconds the clutch is fine and it works well But it is becoming slightly more frequent (once or twice a week.)
the car runs well and has all service history .
it has done 47000 miles -I suppose there is a faint rattle when it start normally but I put that down to being a diesel-I have had it 5 years