Sadly Virgin Media either have to start monitoring the rest of the Internet en masse or they have to trust the information they receive from those ISPs they directly connect to.
The Internet isn't designed to 'heal' from packet loss, it is designed to heal from total loss of connectivity, and even then this requires routing protocols throughout to be working properly and register the loss of connectivity so that they can inform connecting ISPs such as Virgin of this and Virgin can remove that route from their tables and move onto the next one.
Regrettably we are all numbers to Virgin Media, they couldn't give two hoots about any of us so long as we keep buying their pile high, sell cheap, low quality, low cost product. Products like those don't come with guarantees of quality of routing onto the wider Internet, nor even within Virgin's own network.
It may be worth trying to communicate this with second line support, also have a bash with
this and see if it takes an alternate route - that server may be single homed!