The rules seem to imply that the move is mandatory, in that it says, "The player now moves his/her Merchant Figure...."
So ... just move it. That's one of the tensions in this game to think seriously about your moves. If you have only one counter (say the danish) even after playing cards (sometimes you could gain another counter), but if you have only one counter on your side you have to move your merchant accordingly.
Hope that helps and all the best from germany.