OK, so without paying full attention to what I was doing I created a new gmail account this morning while still logged into the school's google calendar. Now the primary email address for the calendar has switched to the new gmail address and the share security on the calendars has gone to pot.

I can't see how to remove this new account as the primary and revert back to the old login. Is it simply a case of deleting the new gmail account or will that wipe out the calendars under the old email address as well?

Yours an utter muppet