I popped into a Carphone Warehouse store last week and just casually asked them if they knew much about the iPhone, just out of interest, to test that theory.
Let's just say they went MAD! I had opened a can of worms and they wouldn't stop talking about it and how excited they were and how every other person coming into the store asks about it. Apparently the CPW website has a counter of the amount of people enquiring about the iPhone there to show the interest. He also said they would be getting large displays in with some sort of demo machine so people could see how it worked and looked on the screen, but I haven't been in since.
I was under the impression it wouldn't be as popular as the US, but maybe it will be a little more than just boring, who knows. Launch day will tell us!