You're not the only one.
I've sent a recorded delivery item to someone in Scotland twice, to two different addresses as the first one came back as uncollected (no card left to say they'd attempted delivery) and the second time it came back as 'undelivered - recipient has moved' - it was his work address, and he was there all day every week day....
so now I'm abouut to mail it out to him for a third time.