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If they've given you an installation date over the phone, that should be when it will occur. It's the ordering via the web that seems to drop into the ocassional black hole, so a CS person telling you the date suggests it is properly in the system.
As for what you should get, I'd expect two separate boxes, the cable modem and TV Set Top Box. Each can be located as you require within the house, provided there is a reasonably accessible route for the cable. Bear in mind they will need to run a cable from the street to your house, there should be a little termination point in the public pavement, whcih may dictate the route of this external cable to be buried in your garden.