Size and supplier for deck hatching for a Feeling 326

Hi all,
does anyone know the exact size (for an order) and supplier of the deck hatches for a Feeling 326?
If I am not wrong, the size is approximately 305 x 445 mm. 
Mine is leaking, more than 30 years old and I want to replace it.
Thanks in advance

Hi Thorsten,
in the architect drawing (Philippe Harlé, july 1987) :  clubfeeling1090.fr/images/Doctech/bateau...astillage%20pont.pdf
The deck hatch is specified as 45 x 32 cm.

Cheers