Yes, it is very weird. And I agree, I have not 'signed'for a parcel for some time either. My delivery guy sees me at my balcony window and I wave and he leaves the parcel/s by the door, but then he knows me and at times is delivering to me daily. One courier driver did ask for drivers licence details. 

Who knows if the buyer does the same as me in that he shows he is home and the driver drops by the door, or if the driver just safe dropped which he shouldn't have done given the SOD paid for. It is all very strange tbh and dragging on and on. He is either a very determined scammer or the driver really did steal the item.