Hi CiS,
I can't comment on what cable broadband is like the Walton area, but to check whether you're on a cabled street you need to enter your postcode here:
http://allyours.virginmedia.com/webs...get-address.do
If you are in a cabled area you do not need a phone line for cable internet.
Again, assuming you're in a cabled area an engineer will turn up and run a cable from the street into your property, they'll ask you where you want it to enter your house, where your TV/computer is etc.
You'll probably be provided with a bog standard cable modem, it's sleek and black, it's not a router and it's not wireless. If you want to set up a network you'll need to buy your own cable router.
This section of the VM website might answer many of your questions:
http://allyours.virginmedia.com/html/help/index.html