Well only his fault if you can prove he didnt try and deliver it. As you have stated, you seen him scurry away and he left a card indicated he did try and deliver it. Just because you never heard him (may be he chapped the door and never seen the bell).
Fortunately, the evidence is in my favour. I had been informed only 20 minutes earlier that the package would be delivered within half-an-hour, so was consciously listening for its arrival. Also, I managed to hear the quiet scuffling of a card being inserted into my letterbox, so I should imagine I would have heard a knock, to say nothing of the doorbell.
Also, I now know that the package had the word 'perishable' printed in large letters on the front. Bearing in mind that I had immediately telephoned RM to complain, and that they said they were going to contact the local depot, someone somewhere should have put these two pieces of information together and arranged an immediate re-delivery. In fact, I now know for certain that the depot were informed as, when I informed the postman who brought the package today that his colleague had not knocked or rung the doorbell, he told me that he had 'knocked on' (a Lanky phrase!).
The fact that he left a card means nothing. It is a well documented occurrence that some postmen don't bother to carry the parcel, they just write a card to say that they have, presumably so they can finish their shift earlier. I have read examples where customers have discovered that their parcels were not even on the van, but left in the depot! Easier for the posties if the customers come and collect themselves, I suppose.