It looks like Conor is correct on the sub domain issue and I will certainly be looking at that solution when I get time but for now, as I have a deadline, I will continue to use my current method which is basically having logic in the config.php file to determine which site I am running on, including a local XAMPP server.
I obviously have to use different .htaccess files as I am not that confident I know how to determine which site I am running on within the .htaccess file itself. I know it can be done but for now I will use different files for each environment.

Tony