I've got no doubt that o2 did what you just suggested - completely gave into Apple's demands!
Looking into my crystal ball (an imaginary one, I grant you) I think there's going to be some sort of announcement around the 25th, with the Apple Expo in Paris, along with which there will be a nice software update potentially with MMS and god knows what else. Looking at the keynote from yesterday there were aspects of the iPhone that *looked* different, and I have a hunch that's a nice clue that there will soon be a fresh update.
I also don't think it's any coincidence that the iPod Touch isn't being released until the 28th. New features (and enhanced iPhone? 16gb perhaps?) along with the announcement for the UK launch - just enough to distinguish it as superior to the iPod Touch so sales do not become too cannibalised by that before the iPhone reaches these shores.
Once again, these are just my thoughts, and are probably completely wrong. The timing just seems right, and something funny is going off at work at the moment.