On the old Ducato (244 Series) the whole headlamp assembly needs to come out. I would imagine the same on the 250.
On the 244, you need to remove the grille as well.
It isn't difficult to figure out what you need to remove, usually two bolts.
Have a look in the light of day, it shouldn't be too difficult.
The owners handbook on the 244 series explains how to remove the headlight, your 250 should as well!!