Not much help, but over here in the states then the postman would have left a note telling you which local post office the package had been taken to, you can then go pick it up or ring them and arrange to have them deliver it again.

I get items shipped from amazon to my work office, sometimes they turn up on a Saturday now the postman knows that the office is closed on a Saturday but the tracking system gets updated with an attempted delivery notice but he comes back on the Monday.

In this instance as the item has been shipped abroad it could just be a case of once the item gets handed over to the UK post office will set the status to attempted delivery, as you've been following it's status did it just arrive in the UK and then get the attempted delivery status or did you see it pass through various UK postal depots?