Renault scenic, think im leaking water

Hi guys,

I have a Renault scenic 1.6 8v 1998 on an S
Noticed on Tuesday the water was just a little below max, so filled it up to about 1/2 inch above max, and today when checking its down to 1/2 inch below max.

The breather pipe is all away up the top so i dont think its going up that far and leaking out, ive not noticed any leaks anywhere, and the temperature gauge is fine, sits just over half way and has done since i got it on the 7th december, ive done almost 800 miles and no problems, heaters are perfect.

So not sure what it is, the last thing i want is the head gasket going, maybe a small leak on the waterpump? again not sure what i need to look for, checked oil cap today and no white gunk in there.

Anyone be of help?
thanks alot