Barry,
I have searched the web, and the most I could come up with is a reference to a castle in Hemmen at
http://oud.refdag.nl/betuwe/980220betu23.html.
The village of Hemmen is built on to Zetten, and its castle dates back to the 12th century. It was destroyed during the battle for Hemmen in 1945. Some of the remains are being restored at the moment so knee-high walls will visualise the layout of the castle.
Was your father involved in the battle for Hemmen in 1945?
Regards,
Hanno