Hi there,
I almost never saw Natrix n. natrix in the wild (of Germany;-), though it is the most common species of snakes in our country, but I see them every day in our terrarium where we keep 2,2 (it's allowed to keep c.b. here). I heard, it's also not allowed to keep them in Belgium). N.n.natrix have these (moonlike) blotches in the neck. HAve a look on the photos on our website:
www.schlangenland.de - Natrix natrix natrix
See you.
Thomas:-)