Ah, now I've had this problem twice now... 1st time I took it to Mr Clutch who claimed that I needed a new clutch (and duly fitted me one). However, 11 months and 16k miles later it happened again - so I decided to go out and check the reservoir (as it says on here) -which was full. So, I then got my wife to press on the pedal and we could here a squeaking inside the engine bay - I tracked it down to an arm that is pushed by the clutch mechanism on the top right of the gearbox/clutch housing aprox 18" inches to right of centre from radiator. The bold holding the arm in place was rusty and movement was not very good so, I got some WD40 on it and hey presto, my clutch works much like new as the arm how has more movement. Needless to say I need to give it a more thorough run and see how it goes but I do see this now as an ongoing maintainance issue.
Rob JE, March 2011