From BARB:
1 – 51k – The F1 Show (Friday, 20:00)
2 – 10k – Malaysian Grand Prix Highlights (Saturday, 12:31)
3 – 10k – The F1 Show (Sunday, 09:58)
4 – 10k – The F1 Show (Sunday, 17:00)
5 – 8k – Korean Grand Prix Highlights (Thursday, 22:00)
6 – 8k – 2005 Season Review: Part 3 (Sunday, 18:00)
7 – 7k – 2005 Season Review: Part 2 (Saturday, 18:01)
8 – 6k – Korean Grand Prix Highlights (Monday, 16:30)
9 – 6k – Legends (Thursday, 19:00)
10 – 5k – The F1 Show (Saturday, 17:00)
The tenth entry in there is the lowest ever for the table, not once before has the top 10 for Sky Sports F1 gone as low as five thousand viewers.
Elsewhere, on ITV4, the final race day for the British Touring Car Championship averaged 318,000 viewers from 10:30 to 19:00 on Sunday 21st October, a very good number for the championship considering the long run-time. On two wheels, highlights of the British Superbike Championship had 215,000 on the previous Wednesday at 20:00.
Over on Motors TV, all of their entries ranged from ten thousand viewers to 20,000 with things such as highlights of the World Rally Championship, British F1 Sidecars and even Tractor Pulling (whatever the latter may be). The channel even reached more people than Sky Sports F1 through the week, 445,000 viewers for Sky F1 versus 450,000 viewers for Motors TV.
Motorsport Broadcasting 
ITV4 are doing a great job with the BTCC. I’ve loved watching it this year.
Haven’t watched too much this year (catch up at Christmas!), but they dedicate a lot of hours to it on Sundays, which no other network would do.
From what I’ve heard SkyF1 hope to be on Freeview HD next year via iptv. Costs & quality is unknown.
Interesting! First I’ve heard about that.
Could have done with it back in March and a free version that’s maybe poor quality with the graphics barely readable and 80s down-the-phone style quality for the audio (to encourage people to subscribe!)