Since August 2006 homepages using a .com TLD have been removed from Google.co.uk results when using the UK filter. This site (www.seoptimise.com) has suffered from the same issue but today I noticed the homepage appearing for a Google.co.uk search for SEO services UK.
After looking into this further it now appears that the issue has been resolved, with UK hosted .com homepages now listed for UK filter queries. For example, the problem was discussed by Freshegg last month, listing madmash.com and tubstore.com as homepages experiencing from this, but site searches for these domains using the UK filter on Google.co.uk now list both homepages.
This follows Matt Cutts’ post about a fix being applied on January 10th:
“An SEO or two has been holding my feet to the fire about root pages of .com’s that are hosted outside the US. Barry has talked about the issue a little bit here. In some (pretty rare) circumstances, you’ll see the root page when you search site:domain.com on google.co.uk for the “search the web” option but you won’t see the root page when you switch to “search pages from the UK”. I thought we’d nailed this issue in December, but we found another way that this can happen. I believe a fix has been submitted and is percolating its way through the system. Of the ~7 examples that I know of, I believe all but one is working now (and the remaining site is doing a chain of like five 302 redirects to weird/long/deep urls). However, if you 1) have a .com that is hosted outside the US, 2) searching on (say) google.co.uk for [site:yourdomain.com] returns your root page and all your pages for “Search the web”, 3) if you switch to (say) “pages from the UK”, the root page does not appear but the rest of your pages do, then this paragraph applies to you. I’d wait 4-5 days to let this second change percolate completely into our index, and if you still see the behavior after 4-5 days, please leave a comment with the name of your site.”