It certainly sounds like the clutch on this one was on it's way out,the system is hydraulic and should be pretty light in operation.
Can't really comment on the brakes though,going on other Clio 2's with different engines in them I can say that brake feel isn't a renowned feature.Once you get used to them though they are fine.
I haven't any experience of the problem,but the 1.5 dCi does seem to suffer from sticking piston rings.This gives cold starting problems and also excessive
consumption,if you go to look at one then try and get there before the engine has been run and try it from stone cold.
If any you look at have sunroofs,then make sure they don't rattle and check for any signs of leaking water into the cabin,both are common faults.Check the power steering works correctly (electronic system,usually reliable but faults can be expensive to remedy),check the cambelt has been changed at 72k/5 years,and religiously check all the electrics are working as they should.
If you buy carefully then the Clio 2 is a good car,there are a few bad ones around though as you have found out after looking at that one today.
That's all I can think of off the top of my head,I'm sure other members will also help out soon.