lucy24 - 7:50 pm on Aug 4, 2011 (gmt 0)
The inquiry:enquiry pair cannot possibly be the only word on your entire page where you had to choose between British and American spelling. All the others were simply words you didn't even think about. If you really want to confuse or annoy the visitor, mix British and American spelling on the same page.
Or get a Canadian to rewrite it for you in the interest of compromise :)