Not sure about the rest of Europe but in the UK second hand or grey imports did not have to go through Euro 1 or 2. and were registered as Emission excempt.. 10000's of cars came in during the 90's. My 2001 Ford Falcon V8 UTE was emission excempt when it came in from Australia in 2004.
Its not just the 1HZ engine that would need to be Euro 1/2 but the whole vehicle. At one time in the UK the 80 Diesel Automatic could not be imported as it would not pass the emission rules yet the manual version would.
On the other LC forum where you asked for a copy of a registration document you have said you are importing a HZJ78 from the UK to Denmark so you need to get the UK registration document (V5) and give this to your country registration department, it cant just be any V5 as its engine number / vin number specific.
If it was possible to do it how you want, the ramifications to stolen cars would huge. Doing it your way if someone steals a car in the UK and could use a photocopy of any V5 to register it, the stolen car would be made official when stolen.
Some 1HZ engine were euro 1/2 but its the specific engine you will have to get past the registration department. Best of luck but i dont think you have much chance without official documentation, you may well also need solid proof of ownership as well