Sky is to launch a separate EPG numbering system for channels broadcasting both SD and HD versions. From February 1, 2011 Sky will run both its “Standard Bouquet” and the new “HD Swap Bouquet”. It means that channels with an HD simulcast that has been allocated a number further down the Sky EPG will be able to take the slot held by the SD counterpart, but only in HD homes.
I don't expect Virgin Media to follow suit, as with the introduction of the TiVo interface the channel numbers become less relevant to viewers. However it does make me wonder though how much longer Sky will continue to broadcast SD versions of its own channels - if they wanted more customers to stump up for the monthly HD subs charge then I wouldn't put it passed Sky to make Sky1 or Sky Atlantic an HD only channel.
Still no official word on the availability of Sky Atlantic on Virgin Media btw.