i'm just making a wild stab in the dark, but i'm guessing that the UK varriant is down to the UK networks wanting to give it a basic approval before it is used on their networks.

For those of you that don't have it, i reckon you have devices using the Vodafone variant, which will go through more stringent testing that the standard UK variant, and probably have some customsing done with special Vodafone apps etc