It has changed transponders to 10847V SR22000 5/6 (the BBC HD transponder) on Astra 2D. and also Channel4 HD has changed to 12607V SR27500 ready to go FTA shortly.
I have got the same problem I am a customer of Sky but I don´t live in UK so I cannot get ITV HD1 in Astra 2D, One good channel HD lost. It was lucky they hadn´t move the only transponder in the south for this channel. I hope at less they don´t move the rest of Itv 1 channels in the south thansponders...
P.D: I must say I never saw a provider that moves constantly channels and frecuencies like Sky, they are really terrible on that
As far as i am aware, Channel4 have leased there own transponder, and they can put any channel they want on it when contracts come to an end, when that is i dont know, but as the transponder is DVB-S2 they can fit 4 HD streams on it, so they can fit all the HD channels on it if they wanted to.