xyz.org redirecting to www.xyz.org at de-dup menu causing session to log out and cryptic "you are not authorised" errors.

this page http://antarqld.org.au/civicrm/contact/deduperules?reset=1&action=browse

links (i think) to dedup rules based on the base URL eg

http://www.antarqld.org.au/civicrm/contact/dedupefind?reset=1&rgid=6&action=preview

notice the new www

the simple fix is to log on to www.antarqld etc but I for one was stumped by this

you could accuse me of bad practice for allowing the log in at http://antarqld.org.au rather than forcing a redirect to the formal base domain http://www,antarqld.org.au

suggestions to rectify - either
1) issue a warning when logged in at a domain other than base URL "Warning you are logged in at xys.org. If you follow some links in civicrm you will be transferred to the base URL defined in your config file (www.xyz.org). In this case you may recieve not authorized error messages until you log in at www.xyz.org"

alternatively
2) use the method used on other cive pages and redirect to relative urls???

thanks again - love all your work you all rock
2)