Skoda Octavia 1.6 FSI 2007 - Buying Advice Please

First things first, I've been driving for 20 years but I don't know much about cars.

I went to see this Octavia today - http://www.ketteringtradecars.co.uk/used-cars/skoda-octavia-1-6-ambiente-5dr-kettering-201501130133595.

Car is in very good condition, and price seems reasonable. On the test-drive I noticed a a slight but still noticable vibration through the clutch pedal on pulling away.

I mentioned this to the salesman - he had tried the car himself and didn't notice it but one of his colleagues who had brought the car up from a Skoda main dealer in Kent agreed with me and said he could feel it too. I explained that it was something that I was concerned about. The long and the short of it is they offered me the car at £2550 with no work on the clutch, or to do the clutch and pay the asking price of £2695.

My questions are:

What might the vibration be (clutch or something else)?

How much would it be to replace a clutch (roughly)?

Any other thoughts - it was a good car otherwise.

Thanks in advance.