There isn't just one mid-pack, there's four different ones with different channels in each:
- Variety
- General Entertainment
- News & Documentaries
- Kids and Music Pack
They are all the same price - listed here:
http://www.ntl.com/customerupdate/pdf/price_list.pdf
edit:
I'm not sure if this is up to date but here you go (all the channels of the base pack are included as well):
Variety Pack
Cartoon Network
Cartoon Network Plus
Discovery
Discovery +1
Discovery Home & Leisure
Fashion TV
Living TV
National Geographic
National Geographic +1
Paramount Comedy
UK Gold
General Entertainment Pack
Bravo
Challenge
Discovery
Hallmark
Living TV
Men & Motors
Plus
Sci-Fi
Trouble
UK Drama
UK Food
UK Style
VH1
News & Documentaries Pack
Biography
CNN
Discovery
Discovery +1
Discovery Animal Planet
History
History +1
National Geographic
National Geographic +1
UK Horizons
Kids & Music Pack
Cartoon Network
Cartoon Network Plus
Discovery Kids
Fox Kids
Fox Kids +1
Nickelodeon
Nickelodeon Replay
MTV
MTV2
Smash Hits
The Box
Trouble