Hi - Have got onto the people who are hosting the site as I dont have access to the cpanel. They came back with the answer below - Do you know if what they say is correct or am I going to cause myself even more problems??
""The server is actually a Windows server, so htaccess files don't work (they are for apache not IIS). Currently both the .co.uk and .com domain both point at the same site.
To achieve what you want to do, you could change the index.html page to a php page and at the top of the code, check if the domain is .com and if do, redirect to the .co.uk domain.""