Turns out some bright spark had confused brentford, Middlesex with brentwood, Essex - despite the clear address and postcode.
The item has now been scanned at Ipswich once more as a missorted item.
A phone call to PF put me in touch with a lovely lady at Ipswich Depot who has told me that the item is definately not there and does not understand how it was scanned as it was. She is now investigating and will call me tomorrow.
Just gets better and better.