Nope, no luck.
Using a laptop. I use the UK version of the United site (by selecting "UK" - I assume there is no other way). It insists that I enter a state/region, but then says that my address is invalid. My house is 35 years old - so not a new build. Have also tried the in-kaw's address in London and no luck with that either...
Is there any other way to join MileagePlus, other than online?