I don't know about the UK, but in the US, my driver was only found on the system resources disk Dell sent with the computer. If you go through the automatically run program, you cannot find it there. You have to open the disk and explore the files.
You have to go your DVD drive and go to ZIPFILES. In ZIPFILES, open the files R214966.zip and R215050.zip. Those should make windows properly install your TV Tuner (I searched the Dell site for those but I didn't find them yet).
My tuner works with windows media center...well, it gets the one channel I can get without an external antenna