i`m currently building teh billings kit just now, i know it`s not waht your after, but i did come accross a few links to grp based nederlands that had been built. pm me.
Try the Hague Model Boiat Club. It is a mine of useful information and you may find a link on there. Alternatively send an E-Mail to one of the many contacts on there and they may point you in the right direction. The link is below.