Welcome to the Virgin Community! I'm massively sorry to learn about the problems you're experiencing with your TV service at the moment, I'd like to take a closer look at the set top box and run some tests from our end for you but I've not been able to locate your account unfortunately.
So I'm able to do that, could you respond to the private message I've sent with the requested information? You can view the message by clicking the purple envelope on the top right of this page.
Also, do you have any additional audio equipment plugged in at the moment? How do you have your TiVo box connected to the TV?