Here is a list of HD channels on the Sky UK system.

Those on a north beam you will have difficulties in receiving on a small dish, and even on a big dish may not be available when the north beam signals are at their weakest - mid to late afternoon.

Eurobird 1 (28.5°E)

ITV HD - free
Rush HD - free
Luxe TV - free

Astra 2A / Astra 2B / Astra 2D (28.2°E)

BBC HD - free - same frequency as BBC1 Channel Islands

Astra 2A South

Channel 4 HD - needs a FSFS viewing card

Sky Screen 1 HD
Sky Sports HD 2
Sky Sports HD 1
Sky Real Live HD
Sky Action HD
NatGeo Wild
The History Channel
Biography Channel HD
Crime HD
Eurosport HD
National Geographic UK
Sky One HD
Sky Box Office
Sky Sports HD 3
Sky Box Office

Astra 2A North

Sky Arts 2 HD
Sky Family HD
Sky Movies Premiere HD
Sky Screen 2 HD
Sky Anytime HD1
Sky Anytime HD2
Sky Modern Greats HD
Sky Drama HD
Sky Scifi/Horror HD
Sky Comedy HD
Discovery HD UK
Sky Box Office
Sky Arts 1
Disney Cinemagic HD U.K.
Sci-Fi HD UK