I have done a full restore on my iPhone 3GS as it was crashing all the time, it must be one of the plugins I’ve installed. Even though there are no issues with the 3GS I still got to restore it. When you already have jailbroken your iPhone, it’s highly recommended to do a full restore again for the new firmware and jailbreak.
At the moment I have tested using Vodafone sim card, will try the Orange once my sister is back from the dentist. Then I will give you an update later today.