Probably. I don't have access to the terms of service for iTunes from this computer. However, Apple does apparently reserve the right to use things such as IP addresses to determine if there is fraudlent territorial access. And, there are anecdotal reports that IP address restrictions have been used to prevent the rental of movies outside the U.S. even by legitimate U.S. account holders. Given that you have both a legitimate U.K. credit card and billing address, you should be within the terms of service but you should read them your self. If you scroll all the way to the bottom of the main iTunes Store window, you can change the store to the UK store and then click on the Terms of Service link at the very bottom.
