200tdi prop vibration???

i have a vibration or a bad vibration on the overun when lifting off going over roughly 50-60mph. this happens on my 200tdi 110. i'm thinking it could be prop but i dont know. it seems to be somewhere int he drive train. the problem has got no better nor worse after 6000miles since i bought it with the problem.
any ideas anyone???
thanks

try takin it orf and turn it through 180° it may be out of balance.

thanks slob, i'm in the land down under at the mo but will do when i return home.