An update, I received a text this morning saying it was all fixed - I try to keep an open mind, but I was rather sceptical. Anyway, my cynicism wasn't misplaced, it's still not working.
Rather annoyed, I rang up asking to cancel, but was told that because I'm still under contract,
I can only cancel when there has been no service for thirty days. So potentially I'm only half-way there. (Does that mean that one could have a contract for a year and only get 12 days of service, and Virgin would consider that acceptable?) A bit annoying because I've been with Virgin for years and only had to sign a new contract because I moved.
I was on the phone for 40 minutes and have at least got an engineer coming out on Friday. Apparently the outage was so big it means it's stopping the equipment connecting - I'm slightly dubious about this, but that's my cynical side creeping in.
Regardless, I'm either fifteen days away from ending my contract, or four months (when contract ends) - I can't see anything swaying me from going elsewhere when the time comes.