We moved in at the end of November, the previous owners of our new house moved across town. We forwarded our mail, even though we only moved locally. The previous owners didn't, so we are still receiving their mail.
We had an informal arrangement to leave all their mail in one of our outbuildings, which is easily accessible from the street, for them to collect whenever they are nearby. They've only picked up their mail three times since we moved in, and that includes packages from a mail-order company.
I don't actually mind about the mail, but they also run a business from home and a lot of the mail is addressed to this business. I realise it takes a while for a change of address to filter down to everyone - we're still getting mail to our 'old' address - but I'm a bit concerned that customers might still think this is the business address.
I asked at the post office and they said as it wasn't my mail, I couldn't do anything about it except 'return to sender'.