@alv31alv I think the area code for most of London is 15 or 3 for London South, but not sure what is classed as London South.
Disclaimer - I don't work for Virgin Media. I'm just another VM user trying to help out. My setup: V6 TV box, Vivid 200 Optical fibre with Hub 3 in modem mode connected to a Netgear R7000 router. Telewest/VM user since 2001.