I think Bing does it by itself. Ensure that your language settings in header are compatible. Not sure whether en-us setting works for UK. Otherwise, I have always seen my websites on all country specific bing websites
optimizing your site for bing.co.uk is same as optimizing it for Google or other search engines. try to get good quality links from sites with co.uk TLD or the sites which are related to UK. try to participate in UK based forums too.