Hi Kim,
I have the same issue, I purchased a new iPhone 4S and since I have received 16 International SMS charges @ 0.45c each, that I have not sent.
I contacted my service provider who were kind enough to spend a considerable amount of time to investigate the issue in which was esculated to a higher technical support level as they to are keen to find out what the issue is.
They called me back as they were very interested in the problem and we went through the process again to ensure that they did not miss anything, they also considered all purchased apps that I had installed in which all were fine.
They could not find what the problem is however they confirmed that the numbers that the SMS were sent to are UK based I have seen the numbers posted on several sites and one of the numbers is the same as the one you posted.
My service providers were kind enough to tansfer me to Apple, I explained the issue to the Apple technical support guy and he to could not help me as they are not aware of the issue or that an iPhone can send silent sms he also said that their would be no reason that Apple would use any UK based numbers or outlets for support.
I turned off imessage and they stopped, I turned on imessage and they started again. The strange thing is I have never used imessage or sms to send messages especially internationally.
My concern is apart from the ongoing cost, If this is part of the imessage process it is very costly compared to SMS as I do not pay for sms service. I also thought that imessage is a free service.
My other concern is if these are silent sms been sent without consent and it is part of the imessage process why have we not been advised of the costs and also of the process, also what other unauthorised communcation is been transmitted without our knowledge.
Joe