Clutch pedal making a 'popping' noise when pressed, help?

Hi all, just recently bought a 2006 Clio MK3 1.5DCi 106 and have noticed a slight problem with my clutch pedal.



After I have driven about 10/15 miles, when i dip my clutch slightly there is a slight pop sound and it feels like a pop under foot. It also happens just as I release the clutch pedal too.



It doesn't affect driving in anyway, just getting kind of annoying.



I've read it could be a self adjuster or something?



Any help would be appreciated!