Or center/centre or aluminum/aluminium. :)
Different spellings of the same word are never a problem. In computing and programming we Brits are used to having to switch to American spelling where required but there can be problems with different meanings.
I think part of the misunderstanding here is that people outside of the UK cannot understand that "inquiry" to us means a formal, organised investigation normally held by a group of people. For example yesterday there were calls in parliament for a public inquiry into the riots in English cities. If someone in the UK had written "calls for a public enquiry" it would look wrong, it would be seen as wrong and it is wrong. ;)
Vive la différence! :)