I've seen many questions here recently asking the same question and I'm here also because I'm in the same boat waiting for the iphone 12 for over a week.
I went ahead and contacted the sales team as suggested and they have no definite answer at the moment. Obviously there is no stock with O2 and their best advice is wait times should be around 1 week, however the stock would be allocated as first come first served so results may vary. Its unfortunate that there's no better answer but this is the way with Black Friday demand during a chip shortage.
