lucy24 - 10:24 pm on Aug 11, 2011 (gmt 0)

On further consideration... I'm not sure an American site would say "[ie]nquiry" at all, unless they wanted to sound insufferably snooty. Probably "Thank you for your interest" or "... your question". So the word itself is part of the overall Britishness. You may not be consciously aware of all your other Britishisms, but visitors will have noticed them. At least subliminally. In this case, Americans will notice the word, while Brits will notice the spelling.