Having signed up for a Reseller account over at Terra Networks, I found out that the Ensim Control Panel (or Parallels control Panel as it is now known as) automatically uses http://<sitename>/admin and http://<sitename>/user for it's administration URLs. This is a bit of a pain as they are the same as the Drupal URLs!
You can redirect the Drupal URLS using the Core Path module. Once enabled, go to http://<sitename>/build/path (or choose URL Aliases from the Administration menu) and set up your redirects there.