I might have mentioned this in the Annoy thread at the time, but I got an email from Vector about six months ago saying that they needed to change the modem, that there would be no interruption to power supply, and that I didn't need to be home. A couple of weeks later they sent a text asking me to ring them to schedule a time for the upgrade.

I didn't feel like jumping through hoops so I ignored it. I have no idea whether they ever replaced the modem!