Double Login required when mapped domain

Hi,

I have a site on multisite (mgocni.teamthing.com) which is mapped to a domain (mgocni.co.uk) using the domain mapping plugin.
However if I navigate to the login screen (http://mgocni.co.uk/login/) and use my credentials it redirects me to the unmapped login page (http://mgocni.teamthing.com/wp-login.php?redirect_to=http%3A%2F%2Fmgocni.teamthing.com%2Fwp-admin%2F&reauth=1).
I have a good understand of why it is happening, but I am wondering if there was some way to stop it from redirecting?

Thanks,

Conor