FYI, the only system changes I made prior to this starting was to select the admin login to use ssl. I've now unselected this, but it is still happening. Do I need to clear something?
FYI. the path I receive is www......co.uk/wp-login.php?redirect_to=%2Fwp-admin%2Fthemes.php%3Fpage%3Dmantra-page&reauth=1
which I assume is where I was when I was making the last change, but with a reauthorise (login) bit put in the way.
Odd.