I would not worry to much about it ... for now .... that is the valve lifter and the sound comes maybe because of the thick oil.
A good ideea would be to change the oil with some more thin oil.
And in the spring I would take a look at the valve lifter and change them if needed or adjust them.
I am more than sure that changin to a thiner oil or adjusting the lifters will help.
Abou the clutch .... when did you last checked the fluid ? The clutch is hydraulic if i am not wrong and the liquid could also get old and think on the cold .... freezing here in Jylland