If the car has a service history, and there is no evidence to support it has had the clutch replaced. It would be resonable to assume it is running on it's original clutch. And given it has covered148km [100k miles] and taking into account what you have described in your post, I reckon your looking at a new clutch mate.
I would get it sorted at your convenience and not wait until it fails on the road. If you do take the car into a garage for a diagnosis let the forum know the outcome..........it helps build the knowlage base mate