Have you got any Ethernet connected devices? Do they also lose connectivity to the Internet? Just trying to establish it is the WiFi that is dropping or the connection to the VM network?
If it is just the WiFi then you could try different wireless channels to see if they are more reliable.
Disclaimer - I don't work for Virgin Media. I'm just another VM user trying to help out so my answers may be wrong :-) If you do like my answer please mark it as helpful as it may help others My setup: Vivid 200 Optical fibre with Superhub 2 in modem mode connected to a Netgear R7000 router. Telewest/VM user since 2001.