After finally getting Exchange 2013 working, and solving why our SMTP connection keeps getting closed (see http://social.technet.microsoft.com/Forums/exchange/en-US/cd03793b-9e99-474e-8f25-11275652882f/exchange-2013-stops-receiving-external-email-after-about-8-hours?forum=exchangesvradmin)
I'm not sure why but in trying to fix the smtp problem, the OWA&ECP IIS virtual directories broke.
I found the commands to recreate the directories and the web application and done so, and OWA is back and working - However ECP now appears but when an administrator attempts to login you are just redirected back to the logon page, if you enter the wrong password you are told "incorrect password etc." which leads me to believe that it is work, just that it's either a permissions/directory security problem or an aspx problem.
Any ideas as to where i should start looking, or has anyone else had this issue and resolved it?