Been having problems with the red button not working on Virgin Central (ch 119 & 120).
Spoke to tech support (after 15 mins on hold) to find that going to BBC1 and pressing the red button then makes 119 & 120 work again.
Been ok for a few days, but went again earlier - had to goto 119 after BBC1 as it didn't like going to 120 first for some reason.
Oh well - sorted for the short term anyway.