Good news!
It is an original Dutch delivered car. The engine number should be 351/173, which should be near the thermostat house on the front of the block. The original colours were Oro Longchamp with a full brown leather interior. First registration was on 30-10-1978 to a private owner.
It left Holland a long time ago. The Dutch DMV go through their books every couple of years for inactive registrations.This one was taken out in 1991, meaning it probably left the country in the late eighties.
I will call my contact who was the service manager for DT in Holland at the time.
He made duplicate records of all DT cars sold and serviced by them and he still has them. All in their own binder, in numerical order stored in filing cabinets. It is quiet amazing that he still has these.
Keep you posted.
Chiel