Hi Gareth. A garage fitted the clutch as they assured me this was the reason that I was having problems. Although when they took it apart, it was apparent that a clutch replacement was necessary, but unfortunately did not solve the issue, if anything it has made it worse. The car has just covered 158000 miles. The garage also told me that if the master cylinder was the cause, then my brakes would have issues also. But I have referred to my Haynes manual and it says that the brakes and clutch have separate cylinders. Think I will replace the master cylinder anyway as that will be the cheapest option to start with.
Thanks