Been with Virgin for over 4 years now and iPlayer has never worked properly. It's soo slow and buffers all the time, god forbid you pause a show as many times it continuously buffers upon restart and you have to restart the show.
An example of how slow iPlayer on Tivo is:
Tivo startup = approx 40 sec just to get to menu
LG smart tv = approx 5 sec
I have spoken to Virgin many times over the years and never get a clear answer. It would be good to be able to use the Tivo as it was sold to me as an all in one media device. But for catch up I tend to use my TV as the Tivo box is just too slow.