[Stuart]

I would imagine it's ultimately Sky's decision which numbers they give which channels on their own platform.

Actually, very far from it. Sky have very little say over where channels are placed on their platform. There are very strict rules which is why when they reorganise it, there are extensive discussions to obtain agreement from broadcasters who actually 'own' their EPG slots.

Most HD channels appear in the 800s range if you don't have the HD sub, except normally for those which are FTA.

My point was that I am surprised Sky haven't done the 'HD Swap' or why ITV have not asked them to do it. It seems odd for ITV to make those channels FTA but not promote them more on the Sky platform.