Hi Karl might be worth contacting me Uk at Milton Keynes it used to be a chap called Malcolm turner but he's left now ask them if they can confirm your of manufacture and original country of origin. Your right the Dvla are tightening up on things won't help when next year anything over 40 years old is going to be mot free !!!
Ask for the unimog department on 0333 4141 906
Keep us informed
Moose