I bought an 04 1.9tdi sport 123k miles 2 weeks ago with the same high biting point on the clutch and in 600 miles I lost all ability to get it into any gear (clutch not disengaging when pressing the pedal). There was a very slight vibration in the clutch pedal during the time I drove it. I was aware that this was an issue at the time of buying and I had absolutely no problems driving it until it completely failed leaving work one day. So it failed very suddenly. I expected to get a bit more mileage out of it before it went but that's the way it goes sometimes.
So I'd keep an eye out for vibrations in the pedal or a slight stiffness putting it into gear when first starting up the car as you may have to replace it like I'm having to.
To check for slipping, you can put it into 1st gear with your foot hard on the brake and slowly bring up the clutch pedal, it should stall fairly quickly if it isn't slipping.
