I take it you live in Hertford, the co-ordinates to use would be 0.0928 West and 51.7931 North.
You can rename/renumber the channels using a program called dreamboxedit on your PC. Personally, I would download a pre-made channel list of your choice and transfer them. Catseye and Vhannibal lists are two popular ones. I have given up on numbers and go through the bouquets.