Hi Atomic ant
I know this is probably too late, and you have already moved, but . . .
When I moved house in 2003 my overseas mail got redirected no problem using the existing redirection service which you have to pay for.

Also as a second line of defence I printed out and left some sheets of sticky mailing labels for the new occupants which read something like:
PLEASE REDIRECT TO:
Ian Cashmore
100 Any Street
Any town
Any County
AN1 0TN
(Obviously I put my own new address

)
Then when the new occupiers got any of my rogue mail, they just stuck one over the incorrect address and put the item back in a post box. As far as I am aware I got every single letter and package that way!!!
The reason for this is in an old Royal Mail 'legislative loophole' which states that a letter (or package) is not properly delivered until it is received by the named individual regardless of the address. The Royal Mail then pay for the onward postage if a "Redirect" sticker is used, kind of like them having to return to sender, but instead forwarding it onto the correct address.
[To be honest, my agent still does this sometimes to pass on mail to me from their office without having to pay for it

]
Sorry for the late reply, but I hope it helps!
Ian
