Odd clutch issue

[fully]

Hi all,

I'm having an odd clutch issue on my manual 118tsi, the clutch is as smooth as butter, (as it should be) but once the car is completely warmed up and I've been driving around for a while the clutch starts to feel crunchy, if that makes sense? it's no longer smooth, there is a completely different feel to it.

Once the car has cooled down a bit, it's smooth again but soon returns to the same feeling after I've been driving awhile!

Any ideas, is that normal? It's actually annoying me