clutch judder.

I had the clutch replaced 10000 miles ago. Fot first few months all ok but then I started getting little bit of judder now and again and it has steadily got worse so that now if it happens, and it doesnt rather confusingly always happen, it can be quite violent. As far as I can see the engine mounts are ok..it was a well branded new cluch kit. There is no slip.Any ideas?? Pug 806 petrol manual 98 2.0. Tks