I have a hunch that they post office attempted to deliver the disks but took them back to the sorting office, neglecting to leave a card, hence the recipient never knew they had arrived. Eventualy the post office will return to sender.
If they havent shown up by the time I return from my trip to WDW (2 days to go now!), Ill do some more and restart the list....I just havent got the time to re-do 5 disks and get to the post office beforehand.
I could do with the recorded delivery reference number so I can check it on my return please.