Just a random thought but could it be that the OP had Virgin ADSL broadband via the phone line and BSkyB dish for TV (I know he says VM, but it was a few years ago and anyone's memory can play tricks).
As some of our Superusers here have advised, there does seem to be some confusion with your current home set up; some pictures would help us identify what you already have in the home. It should look something like the picture apcyberax posted in this thread.
In order to use our Broadband and TV services, you will need that installing if you do not have this set up. Some drilling may be involved.
It has been many years since we last offered a dial up connection via a telephone line - and when this was the case, it would have been our own telephone line. I do not believe it was ever offered out once we were called Virgin Media. We have not offered analogue TV for even longer.
Please feel free to pop us a picture of what you do have installed and we'll be better placed to help you out.
It has been many years since we last offered a dial up connection via a telephone line - and when this was the case, it would have been our own telephone line.
Not necessarily 'your own telephone line' Katie. I certainly had a Virgin dial-up modem ... later to become ADSL ... via a BT landline Katie. Then VM announced that they would no longer support ADSL customers and would transfer them to Talk Talk. I chose not to go to Talk Talk and VM were able to cable me up which involved closing down my BT landline and substituting it for a VM one.
It sounds to me like the feed coming in via your attic is your drop.
Downstairs, in your livingroom, there is no need for the faceplate you're looking for. The likelihood is that the isolator, along with the 'faceplate' that should cover it is in your attic and your TV/broadband was fed via an internal cable from your attic. Or maybe even under the floor.
If you have had Virgin services before and you haven't removed any cabling then there will be no need to drill anything.
If your TV is in the same place as it was the last time you had Virgin, look behind it for a screw on F connector that isn't connected to anything.