Calls made (from the UK) to a mobile phone which is on a contract (or, indeed, on PAYG) with a UK company are always charged at the same rate, irrespective of where that phone is. So, to call you, your wife will pay the normal UK rates (or use up her inclusive minutes) just as if you were in the UK. However you'll be charged 11.5p per minute for receiving the call.
If you phone your wife, you'll be charged 36.6p per minute but she won't pay to receive the call.
http://www.three.co.u...ent_aid=1214305748126
Chris