hmmm, phone cards published minutes are nowhere near the actual minutes you get.
i have been using 1st dial asia, you have to register online, they then give you a london number to call your contacts anywhere in the world. you can use that with your inclusive minutes on you mobile, or landline. it does not have a connection fee, and no maintenance either. if you top up with £20 they give you £30.
it is about 8p per minute and the quality is really good. details on their website.

http://www.1stdial.com/