In the past, (iPhone 6 and iPhone 6S), my husband has gotten our phones in the US and we've used them in the UK. There haven't been any problems. This year, we're getting it from Canada. I understand there is some compatibility issues with ATT or Verizon phones, but do you think there will be any issue if one buys an unlocked phone from the apple store in Canada and uses the iPhone 7 in the UK with a UK Sim? Thanks in advance!