I am also in an area (Mid Sussex) not covered by freeview according to the postcode searches. I even got a TV engineer to come out and test for a digital signal. No way he said, no digital signal, despite having a new ariel 2 years ago.
Anyway last week, I was able to borrow a Toshiba DTB2000 box. Connected it up and within a few mins. 26 channels!!!
The picture did sometimes break up every 3 mins or so, but put on a cheep plug in booster and now no problems and we have three boxes in the house on different TV's.
So much for the earlier information given to us!!
So if you can borrow a box, give it a try, you never know.