405 water coolant level

I have recently got a K reg 405 Diesel and as there is no water tank I
presume you have to fill from the radiator. However, there does not appear to
be any level guide anywhere. Can someone please advise on where the max level
is?

 

There's an expansion tank on the left side of the radiator with the
filler cap on the top. About six inches below the cap there's a ridge
with MAX marked on it and further down more less prominent ridges.

 

Thanks Don,
located the tank and the marker - named "neuvaux maxi" - topped up and
sorted.

Kirst