Correct me if I am wrong, but wasn't the UK's 3G, Edge, GMS/GPRS not fully operational yet when the 8800 came out? Please someone correct me if I am wrong. I just looked at a GMS world map and saw that the UK has great Edge, GMS/GRPS, 3G coverage now, so maybe the phone will be more widely available. Also, at least in the States, iPhone will be sold in Cingular Stores (USA's only GSM mobile phone provider - we still live in the dark times here on the old CDMA networks) and Apple Stores. Maybe that will help out with that too if iPhone is carried by your local mobile phone shops.
I think Apple went with Cingular in the States because it allowed them to create a international phone and give US citizens international coverage. CDMA doesn't work overseas. I had my alltel phone with me in London. It did not work because Alltel and all of the other US mobile providers run on the CDMA protocol excluding Cingular, at least for large providers. So, IMHO, Apple made a good move going with Cingular.
GSM World Maps/Network Information