Khorat,
I'd suggest you contact the good people of
www.wingstovictory.nl
This website describes in very much detail the airwar in/over the province of Zeeland, Netherlands, where Zierikzee is located and it maintains a good database. Several Wellington losses can be found in 1940/41.
Reports are in a mix of Dutch, German (KTB's) and English.
Regards,
Leendert