In some properties the wall socket will have the logo of a predecessor company such as Telewest or NTL, and it should still be fine so longer the the cable is connected.
Self installs are only offered if there has been a service in use at the property in the last few years.
The sockets are VM property & should not be removed, however if the previous occupant was not a Virgin customer or was & then changed provider they may have removed it.
Check on you outside wall for an omni-box which terminates the cable from the street. If this is also missing it gets even more complicated as a repull back to the street cabinet will be required, causing further delays. Omni-boxes are usually brown (as below) but older ones may be grey.
