So I stopped being lazy and found some references to this, and all is working now but just need to clarify a few things.
I found reference to vitualhost setting in httpd.conf, so I checked my server and found no entries here in my httpd.conf.
However I did find a file called vhost.conf and this seems to be how the domain gets resolved to my application directory. Although not clear it seems that if I add a directory called the domain name then this will get resolved.
php_admin_value open_basedir /tmp:/home/default/myserverdomain.com
SuexecUserGroup myuser matrixdomain
ScriptAlias /cgi-bin/ /home/default/myserverdomain.com/user/htdocs/cgi-bin/
AddHandler server-parsed .shtml
AddType text/html .shtml
# Begin user directives <--
# --> End user directives
"vhost.conf" 268L, 10059C
So is it that simple?, just create a directory, called mynewwebsite.com, in the root shown in vhost.conf, place my web application files in this new dir. Then all works OK when I point my domain to my server IP address?
Neillh - a lot less confussed.