As I understand it, If the HD channel is included in your package, it gets moved higher up in the guide and the SD channel gets removed.
e.g.
115: ITV2 -> ITV2 HD
116: ITV2 +1 -> ITV2 +1
176: ITV2 HD -> blank
But what happens if the HD channel is already higher than the SD channel? Does it get moved down the guide, or does it stay where it is?
111: Sky Witness HD -> blank ???
112: Sky Witness -> Sky Witness HD ???
180: Sky Witness +1 -> Sky Witness +1
Thank you